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Re: Some comments and questions on digicams...

Andrew Rodney <andrew@...>
 

on 6/19/01 9:54 AM, samarsh@... at samarsh@... wrote:

This is so, but if one has a given RGB image without a profile in the most
visually pleasing working space - then loading a common CMYK separation target
like Matchprint or SWOP TR001 will give by the numbers results which can be
evaluated using Dans -
*very loose ratios*.
Technically no. There is never a situation where there isn¹t a profile. You
can¹t get to CMYK without first defining RGB. Now you can Assign a profile
that is a Working Space and yes, your conversion to CMYK will be based on
this meaning. The better the original description of the RGB, the better the
conversion to CMYK. As for the numbers having meaning, yes, kind of. IF the
final device really does respond to SWOP TR001 then the numbers you see are
something you can trust. But you better send that file to a device that is
producing TR001. A contract proof, an Iris or any other CMYK device and all
bets are off. The beauty of a good, custom CMYK output profile (as opposed
to some ³generic² conversion or one that isn¹t completely dialed into the
output device) is that the numbers are correct.

There is only a hand in this particular shot in question that needs
correcting. The info palette reports a conversion from the current RGB numbers
(which have not been converted, only opened into a workspace ver5.5) to CMYK
which may be 4c 45m 20y.
The first question is, is the input profile correct and is the output
profile sound? If the input profile is good, the preview is good (assuming
your display is profiled). Does the hand look wrong? It¹s quite possible
that some selective color is necessary.

By Dans rather loose ratio rules for caucasian skintones or light to moderate
values - a sample reaing of 10c 45m AND 40-60y could be considered true.
The critical term here is lose! But how does it look on screen? When
everything works as it should, the numbers back up the preview and vise
versa. BOTH can work. If I trust my display (which I do), then I¹d use the
numbers but I wouldn¹t set them to some figures and disregard what I see.
Ideally both the numbers and the preview support each other. IF the imagery
numbers didn¹t produce a good preview, I¹d start suspecting those numbers!

By simply rasing the 20y tone to 40-60y (through a good mask) makes this
skintone look realistic.
Excellent! You said they look realistic. So the numbers and the preview are
supporting each other. That¹s a beautiful thing.

So I agree that there are no precise known valus for colour (except Pantone
and other quantified flavours of colour). But when it comes to skintone - even
a RGB image can be evaluated to see if it is true or not, using an common CMYK
flavour for number
preveiw.

OR RGB numbers. Let¹s look at it this way; you could be using a multitude of
CMYK output devices so each set of numbers will be different. But if you
always use Adobe RGB 1998, then you could decide what values for skin you
like and do your work there. Then you only need to deal with one set of
numbers. Working Spaces are divorced from the display and output device. So
instead of having to come up with rough recipes for skin to each output
device, you can do this ONCE for your Working Space. The numbers and the
preview (especially if you have a soft proof on) can continue to support
each other. You can even read the Working Space numbers with the output
space numbers if you so desire.

What? There are no trilinear CCD cameras? Or does it depend on the level of
camera?
For single capture, not too many. Fovean has a 3 CCD camera and Sony had one
a few years ago. But the vast majority use a single CCD with a matrix of R,
G or B over pixels and the color is interpolated. For scanning backs
(PowerPhase, Betterlight), these are trilinear CCDs. They are ³scanners on a
stick² and capture true color of non moving images.

So why do many colours and tones appear pleasing, but skintone suffers when an
incorrect workspace is chosen? Do these custom profiles for cameras treat skin
differently to say, other light shades of red (low C, higher MY ratios).
They treat all the colors correctly! Go to http://www.digitaldog.net and the
Tips and tricks page and download my example of skin tone off a D1 with and
without a custom profile. The numbers in the two are IDENTICAL. The previews
look different because one was defined using a custom profile. It¹s night
and day.

Andrew Rodney




[Non-text portions of this message have been removed]


Re: ICC profiles and digi-cam

Ron Bean <rbean@...>
 

Lee Varis <varis@...> writes:

White balance is kind of like applying a profile to the "raw" data.
to which Andrew responded:

I don1t agree because I see a huge difference between an input profile and
the role of white balancing. Again, profiles describe color, nothing more.
White balancing affects the response of the color.
OK, I said "kind of like" not exactly like..
White balance is like a profile in this sense:

When you change the color of the light falling on an object
you're going to photograph, you are in effect changing its
colorspace-- the inherent color of the object doesn't change,
just the way it's "encoded" by the light reflecting from it.

Changing the white balance setting of the camera does *not*
change the data that comes from the CCD, it only describes the
color of the light source-- like assigning a "profile" to it.
I believe some cameras can record the raw CCD data with a "tag"
that tells you the white balance setting on the camera when the
shot was taken, but without altering the data. You can later
change the tag, which again does not alter the data-- just like
assigning a different profile.

At some later time (or more commonly inside the camera), the
white balance setting is used to transform the CCD data so it
looks like what you would have gotten under the lighting you used
when you profiled the camera (or at least close to it). So it's
changing the data from the "light source colorspace" to the
"camera colorspace".

There is a difference in that you can run into things like
metamerism, where a different light source gives you a result
that can't be matched no matter what kind of profile you apply.

Andrew responds:

Because again, the role of the profile isn1t to set or alter gray balance.
It1s only to describe what the camera saw at any given moment.
"What the camera saw" is the raw CCD data, which is not affected
by the white balance setting. The white balance is applied after
the image is captured-- maybe only milliseconds later, in the
camera, or maybe much later, when you transform the raw data into
RGB.

If you like, you can pretend that this after-the-fact
transformation takes place inside a "black box" called the
camera-- just like you can't tell how many colorspace
transformations a file has gone through before you got it.


Re: Some comments and questions on digicams...

samarsh@...
 

Andrew, thank you for the quick reply. I agree with your points from this and previous posts.

To help clarify my original points, I will quickly reply to selected portions of your excellent response:


There is no such thing as known values for skin tone. In RGB, the only numbers that are for
sure are neutrals (R=G=B is neutral in a Working Space). Input spaces can describe a neutral
where R doesn?t equal G or B UNTIL you convert to a working space. Input and output
devices are not necessarily (and not usually) gray balanced where R=G=B. That?s a
fundamental reason we have RGB Working Spaces based on imaginary, synthetic devices. If
you are talking output spaces, the numbers are even more vague.<<

This is so, but if one has a given RGB image without a profile in the most visually pleasing working space - then loading a common CMYK separation target like Matchprint or SWOP TR001 will give by the numbers results which can be evaluated using Dans -
*very loose ratios*.

The untagged digicam image looks wrong in any RGB workspace - or when converting from ANY available profile into the workspace (colmatch). In any print the colours are wrong to the same extent. This is consistent on monitor or output.

There is only a hand in this particular shot in question that needs correcting. The info palette reports a conversion from the current RGB numbers (which have not been converted, only opened into a workspace ver5.5) to CMYK which may be 4c 45m 20y.

By Dans rather loose ratio rules for caucasian skintones or light to moderate values - a sample reaing of 10c 45m AND 40-60y could be considered true.

By simply rasing the 20y tone to 40-60y (through a good mask) makes this skintone look realistic.

So I agree that there are no precise known valus for colour (except Pantone and other quantified flavours of colour). But when it comes to skintone - even a RGB image can be evaluated to see if it is true or not, using an common CMYK flavour for number
preveiw.

This is very subjective, but if an image is judged to be wrong by different people - and this 'equal yellow to magenta if not higher' ratio of Dans DOES work, and the monitor and prints both look better to random independedent observers...then in practice
I disagree.

In this particular case, although there is no exact formula for the skintone - it is VERY obvious that the blue/yellow tones are NOT correct.

I wish that a profile was available - but without one all you can do is try every available profile on the image - and trust the numbers (which have not let me down yet, when it comes to getting a general feel for an image).

There really is a BIG difference here. First, all single capture, single CCD digital cameras see the world in black and white. CCD?s are monochromatic. A scanner users a trilinear CCD and captures true color. The color you get with a single shot camera
is created in the software (it?s interpolated color). It?s a far more complex method of capturing color. Also, the folks that make digital cameras are pretty new to the game and few have previous experience with scanners. Lastly, scanner and camera
manufactures have to decide what they want to do with the color of their devices; funnel it into a monitor like space (so any bonehead likes the color they see), funnel it into some known, standard space like sRGB (good for a definition of color, bad if
you want something more than sRGB) or lastly they can provide the widest gamut color and supply a profile (if they don?t, the image looks ugly in Photoshop 6 since there is no description of this color).<<

What? There are no trilinear CCD cameras? Or does it depend on the level of camera?

So why do many colours and tones appear pleasing, but skintone suffers when an incorrect workspace is chosen? Do these custom profiles for cameras treat skin differently to say, other light shades of red (low C, higher MY ratios). How would a profile know
it was describing a skintone or a light red colour in some other object? Or would all light reds get shifted to the 'correct' colour in a sledgehammer effect.

At the end of the day, the presses are running and you need to get the job done. I for one would love a profile describing the digicam image (tagged or not). If this gets the image into Photoshop with minimal pre conversion editing - then I am happy. Sadly
in my very limited experience - I have yet to open a digicam image which does have a profile, and which does not need major correction to skintone to overcome the lack of profile. Whether or not the skintone would need correction with the use of the
correct profile is another story.

Thank you for your time and input Andrew.

Sincerely,

Stephen.


Re: Some comments and questions on digicams & lack of profiles

Andrew Rodney <andrew@...>
 

on 6/19/01 8:25 AM, samarsh@... at samarsh@... wrote:

But running the cursor over a known value such as a skintone is a totally
different story.
There is no such thing as known values for skin tone. In RGB, the only
numbers that are for sure are neutrals (R=G=B is neutral in a Working
Space). Input spaces can describe a neutral where R doesn¹t equal G or B
UNTIL you convert to a working space. Input and output devices are not
necessarily (and not usually) gray balanced where R=G=B. That¹s a
fundamental reason we have RGB Working Spaces based on imaginary, synthetic
devices. If you are talking output spaces, the numbers are even more vague.

The more I deal with these digicam images, I initially conclude that skintones
are a major problem without profiles of some basic description.
That is certainly the case with many digicam¹s. The D1 is a perfect example.
The problem is assigning a profile that isn¹t really an accurate description
of the camera RGB. As Lee mentioned, picking an RGB Working Space can
produce decent previews and you can even get good neutral balance and tonal
range. But that doesn¹t mean that ALL the colors are correctly defined!
Saturated reds that have a lot of yellow in them is a prefect example of
what happens when you assign a profile using a Working Space rather than a
custom profile. It can get you in the ballpark assuming the profile you
assign is close to the actual condition of the digital file. That¹s usually
not the case. What I see when I assign a custom profile to a untagged camera
file is much better appearing colors (skin tones, saturated colors etc).
Without the profile being assigned (Photoshop 6 is using ColorMatch in my
case to define an untagged file), the color can look pretty good (assuming
the capture really is close to ColorMatch RGB). But with the assignment of
the custom profile, reds, skin tones and so forth appear MUCH better. So the
point is that assigning a profile that is close to the color from the camera
gets you close. Assigning a profile that is really dead nuts on produces
better color. The farther a file is from the profile you assign, the farther
you are from getting the best possible color.

To put this in a photographer¹s analogy: You can get your exposure pretty
close to where it should be and what you see on the light box can be
considered acceptable (let¹s say you are within a 1/3 of a stop). You can
push and pull your film and get closer but there is always a downside to
this as opposed to getting the exposure dead on and running the processing
at normal. Ideally this is what you want (unless you are going for an
effect). The closer you are to the optimal exposure, the better. You can get
close and most people will accept the chrome. That doesn¹t mean that one
should not try and get the most accurate exposure possible. When you simply
assign a Working Space to a file, it¹s like having a light meter that can
swing +/- 1/3 of a stop at any time. It¹s close, but it¹s certainly not
ideal.

It may be 'safe' to simply open a common flatbed scan into a workspace that is
visually 'close' - but digicams seem to be a totally different story. This
seems strange, these are both CCD devices, which seem to behave in totally
different ways when it
comes to opening or assigning a profile. Is this because cameras and their
subjects are put to more 'fluid' uses than a flatbed scanner?

There really is a BIG difference here. First, all single capture, single CCD
digital cameras see the world in black and white. CCD¹s are monochromatic. A
scanner users a trilinear CCD and captures true color. The color you get
with a single shot camera is created in the software (it¹s interpolated
color). It¹s a far more complex method of capturing color. Also, the folks
that make digital cameras are pretty new to the game and few have previous
experience with scanners. Lastly, scanner and camera manufactures have to
decide what they want to do with the color of their devices; funnel it into
a monitor like space (so any bonehead likes the color they see), funnel it
into some known, standard space like sRGB (good for a definition of color,
bad if you want something more than sRGB) or lastly they can provide the
widest gamut color and supply a profile (if they don¹t, the image looks ugly
in Photoshop 6 since there is no description of this color).

I agree with the general consensus - Apple RGB, ColorMatch RGB and other
'weak' flavours of RGB often produce better skintones than sRGB or Adobe RGB
or wider spaces...when no profile is available.
ONLY if the capture is close to anyone of these spaces. That¹s the bottom
line. Apple RGB and ColorMatch RGB are both a lot closer to a monitor RGB
space then other imagery RGB Working Spaces (like Adobe RGB). This is why,
if you take a file that really is in Adobe RGB 1998 verses one in ColorMatch
RGB and view them in an application that simply sends the raw RGB to the
screen, ColorMatch will usually look a lot better. It is closer to a monitor
RGB (especially if you are viewing on a calibrated display at gamma 1.8, D50
or say a PressView which always sets the behavior of the display into
ColorMatch RGB). The data in the Adobe RGB file is just fine and dandy and
looks so in Photoshop 6. But outside of Photoshop 6 in an application that
assumes all color is what gets sent directly to the display, the Adobe RGB
file doesn¹t look as good. The meaning of the numbers is the issue here, not
the quality of the color in the Adobe RGB file!

understand that tagged images from cameras are not viable - but the first
time these images are moved from camera to computer, they should get
tagged...or a drag n drop until should be supplied with the camera. This seems
like a basic concern, even for
the consumer level market.
IF you work in Photoshop 6 EVERY image has to be tagged. If not, Photoshop 6
simply assumes whatever RGB Space you pick in the color preferences.
Photoshop 6 always wants to know the meaning of the numbers. It simply
cannot convert to another space or preview the file without this tag. So if
you don¹t tag the image, it has to assume something. For those that don¹t
believe in profile tagging, they have to be aware of this fact! You can go
through life deciding not to tag a file but a tag is used none the less (and
it is probably a tag you don¹t want). Working with untagged files simply
forces Photoshop 6 to assume a space anyway.

Andrew Rodney


[Non-text portions of this message have been removed]


Some comments and questions on digicams & lack of profiles

samarsh@...
 

I have been following this thread with some interest (understatement).

As a pre press operator, digicam shots are just ONE of the flavours of RGB that may be presented to me, untagged - with no separate profile for use (or even an old fashioned paper message).

I have had very limited experience with these images - but I think that I have been able to spot a 'trend' in this new form of input. I am not sure of the quality level of the cameras taking these shots - or whether they have had internal or external
processing before reaching me (I presume not, since most RGB users would have profile embedding on for a workspace, so I guess these are shots direct off the camera, in standard 24 bit RGB TIFF or JPEG formats).

Whitepoints, blacks and tones which one would presume to be neutral/near neutral agree 'by the numbers'. Whites are balanced 255 RGB, blacks may be balanced 20-10 RGB and neutral greys agree in RGB or LAB readouts. So far, so good...(digital photographers
often lament that highlights blow out, something about available Fstops/whitepoint or something?)

But running the cursor over a known value such as a skintone is a totally different story.

The common trend seems to be a somewhat weak blue channel in the quarter/midtones (for skin)...which translates as a low yellow value in a CMYK conversion or fixed sampler reading.

A recent good example is a technical shot of a product (hardware). A hand is shown working the guts of some bit of hardware...whites/blacks/neutrals seem fine - but yellow is very low in the skin (from poor memory, skintone values were close to 4c 45m
20y).

Globally correcting the blue channel helped the skintone, but the whole image changed - B values in this range were common to the hand, product and background (in my opinion it looked better, but by the numbers readings of what I presume to be greys were
no longer neutral).

A rough marquee selection of the hand, with a select/colour range: reds and a snappy quickmask provided a good enough selection to then alter the blue channel, so only the hand was corrected.

Without seeing the product/hardware in real life, I had to presume that the colour was basically correct - and that this digicam image only had issues with skintones!?

The more I deal with these digicam images, I initially conclude that skintones are a major problem without profiles of some basic description. I have not drawn any conclusions about other colours, but if the white/black/neutrals are right and skin is
wrong - then it can be hard to know what is going on with colour in the rest of file (unless other colour 'anchors' can be found to latch onto).

It may be 'safe' to simply open a common flatbed scan into a workspace that is visually 'close' - but digicams seem to be a totally different story. This seems strange, these are both CCD devices, which seem to behave in totally different ways when it
comes to opening or assigning a profile. Is this because cameras and their subjects are put to more 'fluid' uses than a flatbed scanner?

I dont know as much about photography as I should (shamefully admits).

I agree with the general consensus - Apple RGB, ColorMatch RGB and other 'weak' flavours of RGB often produce better skintones than sRGB or Adobe RGB or wider spaces...when no profile is available. This is a big crap shoot. If I have to pick a profile for
a digicam - I try every available one! Most times it's a generic Kodak DCS (from PhotoCD I think) - or Apple/ColorMatch RGB.

I have yet to find a digicam image that is intended for sRGB - even though many consumer level manufacturers are supposedly aiming their products at this space (or is this just MS/HP hype).

So even though generic or canned profiles are frowned upon in normal cases - for a digicam this seems a basic need (even if not as accurate as it could be, it's gotta be better than a workspace chosen for the most pleasing visual effect).

I understand that tagged images from cameras are not viable - but the first time these images are moved from camera to computer, they should get tagged...or a drag n drop until should be supplied with the camera. This seems like a basic concern, even for
the consumer level market.

As a pre press operator, who attempts to provide a service - I can see more work in hand correcting images from clients which do not have a basic description of the characteristics of their camera. Of course, they will want this work done for free...

I am amazed that this subject does not get more traffic on this list than it does. Are these images not the new 'revolution'?

Sincerely,

Stephen Marsh.


Re: Digital Photo Conversion

Dan Margulis <76270.1033@...>
 

Kiki writes,

When I open HDR files in Colorshop some images are very weak and not
saturated enough.>>

That's par for the course for any method of acquiring images, unless
they're all shot in a studio under the same lighting conditions. *Some*
images are going to have tired colors. If this is just happening once in a
while, you'll just have to cope. If, however, this is happening with a
healthy majority of the images you're getting from this source, you should
consider changing your method of acquisition.

Either way, for the time being you should try opening such images and then
Image: Mode>Assign Profile>Adobe RGB. This will pep up the colors
considerably. This doesn't alter the RGB numbers, only their definitions,
so you can't just send raw RGB data for output and expect to see the
brighter colors. However, if you ever convert to LAB or CMYK, the brighter
colors will be locked in.

In the old model we could take a transparency and adjust color on the
scanner before bringing the file into Photoshop for color correction. Am I
wrong to assume one can tweak an inadequate digital photo and improve it
before bringing it into Photoshop?>>

Not at all. This is the traditional way of doing things, whether using a
scanner or a digital camera. As Photoshop has gotten faster and more
powerful over the years, however, the advantage of doing this is less. At
this point, I don't bother to do it unless there is obviously something
seriously wrong with the original. In that case, it makes sense to try to
make a move in that direction before entering Photoshop.

It seems I recall Dan stating sRGB is a good mode to work in.>>
I don't, except in comparison to, say, Adobe RGB for prepress destinations.
If your images are consistently arriving in a way that favors one RGB
definition over the others, that's the one you should be using, but if it's
Adobe RGB, you'd better be very sure that anybody you work with is on the
same page.

Would it be preferable to ask studios to provide a gray card shot wih
each portrait setting to know where my color is at, since my monitors are
not currently calibrated?>>

It's helpful to have a gray card in the image, but it has nothing to do
with monitor calibration. Human beings have self-calibrating vision that is
easily defeated by a powerful light source such as a monitor. We can't
trust our eyes to determine whether something is gray, no matter how well
the monitor is calibrated. Use the Info palette.

Dan Margulis


Re: ICC profiles and digi-cam-last post

Lee Varis
 

Hi again,

To be fair to Andrew I think I need to clarify a few things,

I wrote:

White balance is kind of like applying a profile to the "raw" data.
to which Andrew responded:

I don1t agree because I see a huge difference between an input profile and
the role of white balancing. Again, profiles describe color, nothing more.
White balancing affects the response of the color.
OK, I said "kind of like" not exactly like.. but Andrew is right a
profile doesn't change the data at all only what the data means. White
balance affects how the raw data of the capture gets converted into some
meaningful RGB - the problem is that many people use custom profiles for
16 bit raw files to perform the same white balance ( now it is true that
it is only the appearance of the color is balanced, the actual RGB
values for neutral might end up being something like 124, 135, 129)
This is kind of dangerous IF you end up using the input (camera) profile
as a work space because it becomes much harder to evaluate things based
on the numbers in the info pallet. You must then convert from this input
profile to the R=G=B workspace - "kind of like" white/gray balancing.

I wrote:
Almost
all digital cameras will perform as well as film does in delivering
neutral color for most scenes even without icc profiles.
Andrew responds:

Because again, the role of the profile isn1t to set or alter gray balance.
It1s only to describe what the camera saw at any given moment. That1s why
you do want to gray balance and then build a profile. That1s why after
building the profile, you want to gray balance for each scene. This
accomplishes two things. It insures gray balance (which sometimes you don1t
want but often do) and it places the capture into a condition that matches
how the original capture was produced to build that profile. So with gray
balance, the profile is valid. The profile will have NO role of the
neutrality of the capture. The profile only records a condition. You have
have a file with a gray and Assign or not assign a profile and the RGB
numbers of the gray will not change a lick.
Andrew describes fairly succinctly the best profiling practice for
digital camera captures here. You certainly will not hurt your chances
for getting good color if you follow this approach. To be fair there are
some cameras which seem to require this approach due to some
idiosyncratic color conversions from their raw data (the Nikon D-1 and
the Kodak DCS 460 come to mind) Again, MOST cameras will deliver a gray
balanced 8 bit RGB where R=G=B when "processed" from the native "raw"
file into an 8 bit Tiff


I wrote, concerning the gray balanced RGB from most camera software:

Once this is done a camera file can be
opened up in Photoshop and assigned any of the standard working spaces
and give you a very reasonable starting place for color.
to which Andrew responds:

No! It will only insure you have a neutral gray. If what you say is true,
you could capture the scene as you suggest and Assign sRGB and Wide Gamut
RGB and you1d get to the same place.
Actually, what I am suggesting here is that you can easily evaluate
general color of the file visually simply by assigning a workspace
profile. Now if you choose sRGB the image may look a bit desaturated or
it may look OK. I doubt that "Wide Gamut RGB would look anything but
over saturated but I hardly consider Wide Gamut RGB to be "standard"
even though technically it is one of the "standard colorspaces in
Photoshop. If you pick sRGB, ColorMatch RGB, Apple RGB or Adobe 1998 the
displayed color won't be radically BAD because all of these spaces are
similar to monitor RGB. Andrew is right however in saying that they
won't be in the same space. They will be "in" whatever space you assign.
I apologize if that wasn't clear. I suggest you try a number of spaces
and pick the one that looks the best to you. If you then adjust the
color to your liking you won't be surprised when you convert to the
desired output space.

Andrew elaborates:

Nothing could be further from the
truth. Assigning a profile only describes to Photoshop 6 the MEANING of the
numbers in the file. As you assign different profiles, the numbers NEVER
change. But the preview (and any further conversions FROM the assigned
profile) will change. IF you have a file that is reasonably close to say
ColorMatch RGB, assigning it ColorMatch RGB will work pretty well. Assigning
any space that moves further from ColorMatch RGB will hose the file (Preview
and conversions) farther and farther from the true meaning of the data.
I tend to be less dramatic in my assessment of the necessity for
"correct" interpretation of the "true meaning of the data" but basically
Andrew is right! I've also found that most digital camera mfgrs. assume
that you are evaluating colors on a monitor and they render their
digital camera captures to look good on a calibrated monitor - that
means the color will be reasonably close to ColorMatch RGB! I've had
good luck with Adobe 1998 as well as sRGB - it kind of depends on the
image. 3D gamut charts aside, these three colorspaces are not that
radically different from each other.


Assuming a digital camera file is in ColorMatch may work or may fail. But if
you actually profile the camera, you know the exact meaning of the numbers.
Realize too that the Working Spaces you can Assign are not based on any real
device. They are synthetic RGB models that work well because they all have
R=G=B as a neutral. You can actually gray balance a digital camera file and
find that this raw capture has data where R, G and B do not equal UNTIL you
convert into the Working Space! Input colorspaces do not insure R=G=B yet
you still have a neutral.
Here is where my experience seems to differ. When I gray balance the
digital camera file using the camera mfgrs. software the numbers (actual
RGB values) end up R=G=B and they stay that way when you open them in
Photoshop (if no conversion occurs) if you use the camera software to
modify the raw data (which is what you do when you save out an 8 bit RGB
file). Now if you really desire to use the raw 16 bit linear data from
the camera and open this up in Photoshop you will need a custom profile
to describe the color that the camera saw otherwise you will be pretty
lost. I mentioned this before:

Neither of these approaches
will be quite as good as using a VERY good "custom" profile for the 16
bit "raw" data file but both of these approaches are much more practical
for the vast majority of images you need to capture.

I don't generally find it necessary to work with raw 16 bit data for
most images.

I wrote:

The benefits are not great enough to
warrant the extra trouble either - it is expensive and time consuming to
get a custom profile that would be better than simply assigning a
workspace to a white/gray balanced file for even 50% of the subject
matter you are likely to photograph.
Andrew responds:

Depends on the camera and what the raw data is. Be my guest and assign any
Working Space to a Nikon D1 image and I assure you they all look like crap.
...Raw D1 RGB isn1t anything like any of the
supplied RGB Working Spaces. You can1t assume that an input device is
creating RGB that is in any way close to an RGB Working Space you might
have.
Andrew is again correct as far as "raw" data is concerned and certainly
the Nikon D-1 is fairly goofy if you simply interpret the "raw" data as
an RGB work space. I really wasn't talking about "raw" data though. All
of the cameras I have worked with will deliver an RGB "processed" file
in 8 bits which behaves fairly reasonably if you assume an RGB workspace
- any deviation from ideal can be handled with a Photoshop correction
that you can save and use for every file you open from the camera. There
is a theoretical advantage to delaying and minimizing color conversions
by using input profiles with camera files and that is what Andrew is
championing here and I can't find fault with that approach. I don't
bother with this myself for commercial work and it seems to work fine -
there's always that little nagging feeling that it could be a little
better though so if it helps you sleep better at night...

I write...

For instance, if you manually white balance a sunset scene you will "balance
out" the overall red color and completely destroy the feeling of the
sunset in the image. It is the same thing with profiles.
Andrew responds:

No, input profiles don1t change the data, they only describe the data. IF
you built a profile assuming a white balance, you have to white balance.
That act of white balance hoses your sunset, not the profile.
OK, he got me again.... Yes, profiles don't change the data they only
describe the color. White balance is not exactly like a profile because
it changes the data! Now if you are foolish enough to shoot a Gretag
Macbeth DC target in sunset light to build a profile for sunset lighting
you will hose the sunset because you will normalize the interpretation
of the color to the red sunset light - neutralizing the red even though
you don't change the data!

I write:

I think the challenge for photographers or anyone dealing with
digital photographic images is to create great images by interpreting
color in the most emotionally satisfying way.
Andrew responds:

How do you interpret 11s and zero1s? That1s all a digital file is. That is
why Photoshop 6 needs the proper profile to be assigned. Now you have
properly interpreted the data for Photoshop 6 to provide a correct preview.
You1ve got the meaning of the numbers necessary to convert to a Working or
Output space. Once you take your 3great2 image and Assign the wrong
profile, it1s not so great anymore, at least visually.
Well... I don't really interpret one's and zero's I look at the image on
my monitor and decide if I like it or not. If you assign an RGB
workspace to any RGB file it may not be technically correct or look very
close to the original physical object but it will look like SOMETHING
and it has been my experience that it's not that hard to make it look
like what you want it to look like. If you can't decide what you want it
to look like then a profile may provide some some feeling of security
but not having a custom input profile is not going to be such a disaster
either. Photoshop does not care if you assign the "proper" profile -
even if you do not assign any profile Photoshop will simply assume
whatever workspace you've set for the default and present you with an
image that you CAN evaluate and interpret.

Andrew is correct in saying that if you have a good profile for your
camera you can have a good preview of the color on your monitor and this
would be ideal because you could minimize the actual color transforms to
get your image into a printable form. What I am saying is that to get
great color you WILL have to apply some judgment and creative control
over the rendering of that color whether it utilizes a custom input
profile or not. You can get good color without using custom input
profiles as long as you are properly utilizing the other aspects of a
color managed workflow. You MUST have a reasonably good profile for your
monitor IF you are going to be evaluating colors visually. You MUST have
a good profile for your desktop inkjet printer IF you are going to be
doing any cross-rendering (like simulating a press on your Epson
printer) or softproofing to the monitor. These activities make producing
good color easier with digital camera images because there is no
physical point of reference for color like a piece of film. If you do
not have a calibrated/profiled monitor then you are going to have a
really hard time interpreting anything very meaningful from one's and
zero's (not impossible though)

I'm going to end here by saying that custom input profiles for digital
cameras are NOT A BAD THING. In fact, in some circumstances, they can be
a VERY GOOD THING

Let me say, however, that you CAN get by without them WITHOUT monumental
effort though you may derive a measurable advantage in using custom
input profiles if you are having a lot of trouble with your camera's
color. I have not found a camera yet that produced files that I couldn't
work with without resorting to custom profiles.

Let me also say that Andrew knows a lot more about profiling digital
cameras than I do and I believe that he can profile a camera to render
better color out of the box than I can get without using a profile - I
will have to make some corrections to be better than his first try and
this could be very valuable to someone who shoots catalogs of hundreds
of shots. I also believe that in the next couple of years this will get
much easier to do. I also am looking at a number of different profiling
options myself because I am convinced that there are some creative
applications for the use of ICC profiles. I am hoping that I don't have
to purchase a $3000 package to get profiles that I will have to edit
anyway - Photoshop does a lot more than any profiling package and it
only costs $900.

OK Andrew, I'm bracing for your one-two knockout punch......


--
regards,

Lee Varis
varis@...
www.varis.com
888-964-0024


ICC profiles and digi-cam

Ron Kelly <abcolor@...>
 

Lee Varis wrote:

We can expect to
get good color right out of the camera but mostly, even with film, we
simply get what we get and call it good or adjust it in some way after

the fact.
Mr. Varis:
Thanks for that concise appraisal of this thread; like many
photographers who still shoot exclusively film I have been keeping an
eye on the digital business. It's good to hear from someone who has lots
of experience shooting digitally as opposed to those with "store bought"
opinions; I can read spec sheets too. What you say makes a lot of sense
to me.

Cheers,
Ron Kelly


Re: Digital Photo Conversion

penneykid@...
 

You need to have a good calibrated monitor and then try out various color
spaces to see which one seems to fit the best - usually Adobe RGB or
ColorMatch RGB are good starting points for these types of cameras.
Unfortunately, there's really no alternative to opening up each individual
image and making corrections. The good news is, with a calibrated monitor
and a good output profile, you should be able to nail your color on the
first proof, eliminating subsequent rounds of proofing and cost.
First my apologies Dan for incorrect protocol, I hope this one is OK.

Now on the subject: When I open HDR files in Colorshop some images are
very weak and not saturated enough. One can adjust toning curves or move
color by means of gradation or global color in Colorshop. Then shapening is
added when exporting a file to edit images in Adobe Photoshop. If I try to
adjust color after it has been exported the results are not too good.
In the old model we could take a transparency and adjust color on the
scanner before bringing the file into Photoshop for color correction.
Am I wrong to assume one can tweak an inadequate digital photo and
improve it before bringing it into Photoshop?
My preferences are currently set to keep profile in sRGB in both applications.
It seems I recall Dan stating sRGB is a good mode to work in.
Would it be preferable to ask studios to provide a gray card shot wih each
portrait setting to know where my color is at, since my monitors are not
currently calibrated?

kiki perez
penneykid@...


Re: ICC profiles and digi-cam

Andrew Rodney <andrew@...>
 

on 6/18/01 7:50 AM, Lee Varis at varis@... wrote:

White balance for digital camera files is intended to match the color
response of the capture to the color temperature of the light source. It
is relatively easy for manufacturers of digital cameras to build into
their software "developers" a number of different color responses - this
means more choices for the photographer which is mostly a good thing.
White balance is kind of like applying a profile to the "raw" data.
I don¹t agree because I see a huge difference between an input profile and
the role of white balancing. Again, profiles describe color, nothing more.
White balancing affects the response of the color. That¹s a good thing. But
a profile only works when it reflects the capture. That is, if one captures
a file and that method doesn¹t match how a profile was created in the first
place, the profile is invalid. You may end up with perfect ³white balance²
or whatever but when you apply the profile, the results will suffer. So
ideally one gray/white balances and shoots a target like the ColorChecker
DC. Then they build the profile with this gray/white balance in place. It¹s
like ³calibrating² the camera so it¹s capture is consistent and the profile
remains valid. No matter how you gray/white balance (or don¹t), you don¹t
get a description of the RGB data to provide Photoshop 6 without a profile.

The danger is that one can easily overcomplicate the whole thing. You can
create profiles to use with every white balance setting which becomes
sort of like applying profiles on top of profiles.
No, it¹s more like having a slew of profiles to reflect a slew of balances
which is complicated and usually not necessary.

Almost
all digital cameras will perform as well as film does in delivering
neutral color for most scenes even without icc profiles.
Because again, the role of the profile isn¹t to set or alter gray balance.
It¹s only to describe what the camera saw at any given moment. That¹s why
you do want to gray balance and then build a profile. That¹s why after
building the profile, you want to gray balance for each scene. This
accomplishes two things. It insures gray balance (which sometimes you don¹t
want but often do) and it places the capture into a condition that matches
how the original capture was produced to build that profile. So with gray
balance, the profile is valid. The profile will have NO role of the
neutrality of the capture. The profile only records a condition. You have
have a file with a gray and Assign or not assign a profile and the RGB
numbers of the gray will not change a lick.

Once this is done a camera file can be
opened up in Photoshop and assigned any of the standard working spaces
and give you a very reasonable starting place for color.
No! It will only insure you have a neutral gray. If what you say is true,
you could capture the scene as you suggest and Assign sRGB and Wide Gamut
RGB and you¹d get to the same place. Nothing could be further from the
truth. Assigning a profile only describes to Photoshop 6 the MEANING of the
numbers in the file. As you assign different profiles, the numbers NEVER
change. But the preview (and any further conversions FROM the assigned
profile) will change. IF you have a file that is reasonably close to say
ColorMatch RGB, assigning it ColorMatch RGB will work pretty well. Assigning
any space that moves further from ColorMatch RGB will hose the file (Preview
and conversions) farther and farther from the true meaning of the data.
Assuming a digital camera file is in ColorMatch may work or may fail. But if
you actually profile the camera, you know the exact meaning of the numbers.
Realize too that the Working Spaces you can Assign are not based on any real
device. They are synthetic RGB models that work well because they all have
R=G=B as a neutral. You can actually gray balance a digital camera file and
find that this raw capture has data where R, G and B do not equal UNTIL you
convert into the Working Space! Input colorspaces do not insure R=G=B yet
you still have a neutral.

The benefits are not great enough to
warrant the extra trouble either - it is expensive and time consuming to
get a custom profile that would be better than simply assigning a
workspace to a white/gray balanced file for even 50% of the subject
matter you are likely to photograph.
Depends on the camera and what the raw data is. Be my guest and assign any
Working Space to a Nikon D1 image and I assure you they all look like crap.
Assign a custom profile and the color and even tonal range appear much
better because the data was just fine, the preview was hosed in Photoshop 6
because Photoshop 6 didn¹t know what the proper meaning of the raw numbers
were and just assumed whatever RGB Working Space you pick in the color
preferences for untagged data. Raw D1 RGB isn¹t anything like any of the
supplied RGB Working Spaces. You can¹t assume that an input device is
creating RGB that is in any way close to an RGB Working Space you might
have.

For instance, if you manually white balance a sunset scene you will "balance
out" the overall red color and completely destroy the feeling of the
sunset in the image. It is the same thing with profiles.
No, input profiles don¹t change the data, they only describe the data. IF
you built a profile assuming a white balance, you have to white balance.
That act of white balance hoses your sunset, not the profile.

I think the challenge for photographers or anyone dealing with
digital photographic images is to create great images by interpreting
color in the most emotionally satisfying way.
How do you interpret 1¹s and zero¹s? That¹s all a digital file is. That is
why Photoshop 6 needs the proper profile to be assigned. Now you have
properly interpreted the data for Photoshop 6 to provide a correct preview.
You¹ve got the meaning of the numbers necessary to convert to a Working or
Output space. Once you take your ³great² image and Assign the wrong
profile, it¹s not so great anymore, at least visually.

Andrew Rodney


[Non-text portions of this message have been removed]


Digital Photo Conversions

penneykid@...
 

Can someone point me to a good source to understand how to take
Digital Photo's from Scitex Leaf, Canon and Kodak DCS; convert
Portrait shots from their software over to Adobe Photoshop.
I understand most Photo studios may use gray cards to assist one in
getting the correct color balance. The shots I'm currently recieving
do not contain such so we have no idea where to go with these shots.
I have begun looking at manuals but I agree they are not very good at
going into detail as to what you do with a capture once it is shot.
I'm taking these RGB files and exporting them into Photoshop and
making all my color moves there.
I do catalog work and prefer not to spend time on making color moves
for each individual image at first. I would like to get them all in
good range, proof, then make all my individual moves later.
However the color range I am getting currently from these files is not
good.
Thanks in advance


Re: ICC profiles and digi-cam

Lee Varis
 

Hi all,

I have been a working commercial/advertising photographer for 25 years
and have been involved in digital imaging for the last 15 - capturing
photos digitally almost exclusively for the last 2 years. My current
views on digicams, icc profiles, ect.. in response to some of the
questions in this thread:

regarding white balance and profile issues:

The E10 has seven white-balance settings, plus "manual" and "raw".
Would you need seven different profiles, or does it depend more
on having a good *match* between the white balance setting and
the actual lighting conditions?
White balance for digital camera files is intended to match the color
response of the capture to the color temperature of the light source. It
is relatively easy for manufacturers of digital cameras to build into
their software "developers" a number of different color responses - this
means more choices for the photographer which is mostly a good thing.
White balance is kind of like applying a profile to the "raw" data. The
danger is that one can easily overcomplicate the whole thing. You can
create profiles to use with every white balance setting which becomes
sort of like applying profiles on top of profiles. The thing to remember
however is that for most of the history of color photography a choice
between "daylight" and "tungsten" has been good enough to get high
quality images that could be scanned and converted into good color on
press even without profiles.

If you used the "manual" setting
all the time (ie, point the camera at something white and push a
button that says "define this as white"), could you use one
profile for everything?

Most consumer oriented digital cameras do some sort of "auto" white
balance where the brightest thing in the scene is assumed to be white
and the color is neutralized to that. This works surprisingly well for
scenes with a full range of values. It will fall apart where you have
more limited value ranges or monochromatic scenes with a dominant hue.
If you know the color temperature of the light and you can pick a
setting that matches it you WILL get a color response that will render a
neutral gray as neutral. In the real world nothing is ever very certain
and picking a color setting manually is a guess at best. If you can
perform a "manual" white balance you are way ahead of the game. Almost
all digital cameras will perform as well as film does in delivering
neutral color for most scenes even without icc profiles. This does not
mean that digital captured color will be perfect any more than
Ektachrome will capture prefect color every time. With high end digital
cameras you can capture a target (like a Macbeth color chart or a
Munsell chart) that has neutral gray patches and calibrate to the gray (
forcing RGB values to be equal). Once this is done a camera file can be
opened up in Photoshop and assigned any of the standard working spaces
and give you a very reasonable starting place for color. The only time a
custom profile will be of any value is when you desire to work with 16
bit "raw" data from the camera in Photoshop. The short answer is that
you CAN use one profile for everything that has been manually white/gray
balanced or you can simply ASSIGN one of the standard working spaces to
the white/gray balanced file in Photoshop. Neither of these approaches
will be quite as good as using a VERY good "custom" profile for the 16
bit "raw" data file but both of these approaches are much more practical
for the vast majority of images you need to capture.

Regarding custom profiles for lighting situations:

It seems to me it would be better to shoot a color target each
time and use that to generate a source profile on the fly
(I assume there is software that could do this without manual
intervention).
It seems to me that this would be far more trouble than it is worth
because to my knowledge there is no software that can do this without
some kind of manual intervention and there are plenty of times when you
simply can't shoot a target. The benefits are not great enough to
warrant the extra trouble either - it is expensive and time consuming to
get a custom profile that would be better than simply assigning a
workspace to a white/gray balanced file for even 50% of the subject
matter you are likely to photograph.

...my question was whether one profile is correct for all
lighting conditions.
Nothing can possibly be "correct" for all lighting conditions. Even if
you white balance every shot you can screw up the color because there is
always an emotional component that can never be fully accounted for. For
instance, if you manually white balance a sunset scene you will "balance
out" the overall red color and completely destroy the feeling of the
sunset in the image. It is the same thing with profiles. If you apply
ANY automatic color compensation scheme you are bound to generate a
majority of mediocre images unless you ALSO apply some intelligent
interpretation along with that automatic "correction". We can expect to
get good color right out of the camera but mostly, even with film, we
simply get what we get and call it good or adjust it in some way after
the fact. I think the challenge for photographers or anyone dealing with
digital photographic images is to create great images by interpreting
color in the most emotionally satisfying way. With all the controls we
can exert digitally we should not have to stop at "pretty close" nor
should we have to agonize over what the "correct" color is. Experience
working with Photoshop's color controls can make the task of generating
GOOD color relatively easy and painless especially with images that we
capture digitally.

--
regards,

Lee Varis
varis@...
www.varis.com
888-964-0024


Re: undocumented "features"

Dan Margulis <76270.1033@...>
 

Harold writes,

Do you know of a source for any of the "undocumented features" of canon
equipment. I find it so amazing that it is not possible to find addiquate
documentation for our equipment. In years past most good equipment was
sold with adiquate documentation. Now half the Photoshop manual is "see
online or CD for complete explanation of this feature". This is very sad.
I expect this crap from Epson but not Adobe, Canon, and Nikon.>>

The sort of thing we were talking about won't be found in any
documentation. That a lot of devices behave better in Apple RGB or
something similar is because some engineers somewhere along the line
thought that that was what people wanted and put in a few kludges that
nobody knows about, least of all the people involved in preparing the
documentation.

As for Canon and Nikon, they have the difficult chore of coming up with
documentation for some of their lower end products knowing that some
professionals will use them but that 99% of the users won't be
sophisticated.

Adobe's documentation, IMHO, is generally tops in the industry, with the
notable exception of the Photoshop 5 release. However, Photoshop has become
such a behemoth that to do a truly comprehensive user manual would take
1000 pages. I think what they offer is a reasonable coompromise.
Dan Margulis


Re: ICC profiles and digi-cam

Andrew Rodney <andrew@...>
 

on 6/17/01 6:52 PM, Ron Bean at rbean@... wrote:

Right, but my question was whether one profile is correct for all
lighting conditions.
If you gray balance (and you want neutral gray) then one profile *can* work
in some situations. The jury is out if this is always the case or just
sometimes the case.

Andrew Rodney


Re: ICC profiles and digi-cam

Ron Bean <rbean@...>
 

Im not sure what this has to do with a camera profile for a digital camera.
Profiles dont correct, they describe. With the right description, NOW you
can view the image properly, convert to a Working or output space and get on
with your work.
Right, but my question was whether one profile is correct for all
lighting conditions. If it's sometimes a little off, then you'll
need more correction in those cases. If it's always right on,
then in theory you won't need any correction much of the time (at
least, that's what some people seem to be hoping). For example,
traditional film photographers, using a type of film they're
familiar with, expect to get good color right out of the camera--
their fear is that the printer will screw it up rather than
improving it.

Obviously if you're shooting in a studio, then you have total
control and it's not an issue (in that case it's more like
profiling a scanner). But in the field, lighting varies (like
having a scanner with an inconsistent light source) and the
results will depend on setting the white balance correctly. But
does that completely compensate for the differences in lighting,
or does it always require some hand work?

Sometimes the budget doesn't allow for any handwork. In that case
you could argue that it doesn't matter, the customer gets what
they get. But it would be nice to be "pretty close".


Re: ICC profiles and digi-cam

Andrew Rodney <andrew@...>
 

on 6/16/01 11:40 PM, Ron Bean at rbean@... wrote:

I can imagine two cases-- either the quality is important enough
to correct by hand, or it's not important enough to do anything
more than pick the right preset for color balance. Are there any
in-between cases? Maybe a case where you're dealing with a large
number of images, and don't want to hand-correct each one.
I¹m not sure what this has to do with a camera profile for a digital camera.
Profiles don¹t correct, they describe. With the right description, NOW you
can view the image properly, convert to a Working or output space and get on
with your work.

Photoshop needs a description of the color of a file to properly preview it
to you and then to convert to some other space. If you shove an untagged
file at Photoshop, it simply assumes that the file is in the preferred
working space you set in color preferences. Say you have ColorMatch RGB set
there. Every untagged file from a digital camera is assumed to be in
ColorMatch RGB. IF the file is in that space (unlikely) or even close, then
the preview looks fine and the resulting conversions will be OK. But what if
your digital camera doesn¹t produce RGB that is in any way similar to any
RGB Working Space you have loaded in the color preferences (or you assign)?
You get ugly looking color. Yes, you can try and ³fix it² but there is
nothing wrong with the color. And this fixing is counter-productive! The
file isn¹t broken.

Example. In the Kodak DCS line of pro cameras, I can ask for a 12 bit,
linear file. This is exactly what I want for profiling and control over this
data because it insures I get raw (no auto corrections) from the acquire
module. I profile the camera capturing this data. When I open the file in
Photoshop 6, it¹s untagged. It looks VERY bad! It¹s dark and the colors look
pretty awful. That is because Photoshop 6 is assuming (in my case) that this
raw, linear data is ColorMatch RGB. It¹s not. You can Assign any number of
profiles you might have and it looks awful. Now simply assign the correct
profile (the one that was made using linear capture) and the preview looks
beautiful! The colors are looking great, the dark preview is gone. Was the
data changed? NO. Was the file every poor to begin with? NO. The key here
was having a description of the RGB data the camera produced and then
assigning that profile for Photoshop 6 to produce the correct preview AND
convert into the Working Space.

You basically get two choices with digital cameras; you get raw data that is
undefined (so you have to define it with a profile). Or you get a camera
manufacturer that forces (or funnels) the color into something ³common² like
sRGB or perhaps ColorMatch RGB. Both methods have advantages or
disadvantages. But in both cases, you have a clear definition of the color.
That¹s what¹s key here. From this point on, color correction comes into
play. This part has NOTHING to do with profiles.

Andrew Rodney


[Non-text portions of this message have been removed]


Re: ICC profiles and digi-cam

Ron Bean <rbean@...>
 

DMargulis@... writes:

Just because white has been balanced doesn't mean that black has
been or that a midtone gray has been.
True, but I don't hear anyone complaining about it. They could
have included an 18% gray balance, since you can get an 18% gray
card at any photo store.

It seems to me it would be better to shoot a color target each
time and use th at to generate a source profile on the fly (I
assume there is software that could do this without manual
intervention).>>

Considering that one is probably going to open the file to
examine the numbers anyway, this seems like an unduly
time-consuming solution,
How time consuming is it to take one (1) extra shot with the
color chart? I was assuming the profile conversion would be
automated, if not then it's probably not worth it in any case.

When people first started talking about digital color management,
I think some of them were hoping it would improve the quality of
low-budget jobs, where they don't really pay much attention to
the color. Of course, if the customer doesn't care about quality
in the first place (and a lot of them don't) then they're not
going to bother setting up the profiles properly.

I can imagine two cases-- either the quality is important enough
to correct by hand, or it's not important enough to do anything
more than pick the right preset for color balance. Are there any
in-between cases? Maybe a case where you're dealing with a large
number of images, and don't want to hand-correct each one.

not to mention the fact that there are
a lot of situations, like photographing a football game on Sunday
afternoon, where the lighting changes every 30 seconds and
there's no time to reprofile every time a touchdown is about to
be scored.
In other words, it varies from one job to another. Some people
shoot nothing but sports, others never shoot sports (this is a
common split in the photography newsgroups, since it puts different
demands on the equiment).


Re: E10 Camera

Dan Margulis <76270.1033@...>
 

--------------- Forwarded Message ---------------

From: Harold Barker <hvb@...>
To: Dan Margulis, 76270,1033
Date: Fri, Jun 15, 2001, 5:16 PM

RE: Fwd: Re: [colortheory] Digest Number 144..now E10 camera



Do you know of a source for any of the "undocumented features" of canon
equipment. I find it so amazing that it is not possible to find addiquate
documentation for our equipment. In years past most good equipment was
sold
with adiquate documentation. Now half the Photoshop manual is "see online
or
CD for complete explanation of this feature". This is very sad. I expect
this crap from Epson but not Adobe, Canon, and Nikon.



DMargulis@... wrote:
particular device. Many of these cameras have undocumented internal
routines
that make their output more suitable for something like Apple RGB than for,
say, Adobe RGB. Others don't.


Re: ICC profiles and digi-cam

Dan Margulis
 

Ron writes,

I've always wondered about this. Traditionally, photographers divided the universe into "daylight" and "tungsten", and this was considered sufficient (flourescents were considered hopeless).>>
Sure, just as printing from video captures or from scans of Polaroids or printing full page ads from 1 mb captures was hopeless, but nowadays we have to do all these things regularly, as well as deal with a large number of images that were taken under flourescent lighting.

The E10 has seven white-balance settings, plus "manual" and "raw". Would you need seven different profiles, or does it depend more on having a good *match* between the white balance setting and the actual lighting conditions? If you used the "manual" setting all the time (ie, point the camera at something white and push a button that says "define this as white"), could you use one profile for everything?>>
Just because white has been balanced doesn't mean that black has been or that a midtone gray has been. Yes, it's better than doing nothing.

It seems to me it would be better to shoot a color target each time and use that to generate a source profile on the fly (I assume there is software that could do this without manual intervention).>>
Considering that one is probably going to open the file to examine the numbers anyway, this seems like an unduly time-consuming solution, not to mention the fact that there are a lot of situations, like photographing a football game on Sunday afternoon, where the lighting changes every 30 seconds and there's no time to reprofile every time a touchdown is about to be scored.

Dan Margulis


Re: ICC profiles and digi-cam

Ron Bean <rbean@...>
 

Dan Margulis <76270.1033@...> writes:

The less consistent your shooting conditions are, the less likely there'll
be any benefit to a custom profile.
I've always wondered about this. Traditionally, photographers
divided the universe into "daylight" and "tungsten", and this was
considered sufficient (flourescents were considered hopeless).

The E10 has seven white-balance settings, plus "manual" and "raw".
Would you need seven different profiles, or does it depend more
on having a good *match* between the white balance setting and
the actual lighting conditions? If you used the "manual" setting
all the time (ie, point the camera at something white and push a
button that says "define this as white"), could you use one
profile for everything?

It seems to me it would be better to shoot a color target each
time and use that to generate a source profile on the fly
(I assume there is software that could do this without manual
intervention).

Even in a non-ICC workflow, this would give you a lot of
information about the lighting conditions. Since the
highlight/shadow/neutral numbers were traditionally considered
sufficient data for color correction (with the rest being
subjective), does this imply that the manual white balance
setting is sufficient to normalize the camera's behavior?