Date   

Questions and grain

gowens01@...
 

Thank you all for your constructive comments about my color settings.
Some of you mentioned "learning the numbers". I need to know what
this means. and is the subject covered in Dan's book Professional
Photoshop 6?

Because of weather conditions and low light situations I find myself
using more high speed film 800, 1600, etc. Because the faster films
tend to grainy I found this can create a problem when the negative is
scanned. For a regular 8x10 I usually set unsharp at amount 120;
radius 1.0; threshold 5. (I scan most negatives at 300 dpi). But when
you are using 800 or 1600 speed film the picture will be more
graining as the amount is raised. Then you get things like white
spots in dirt forgrounds. So the last time I used 800 speed film I
set the amount to 60 and got a better result.

Kodak has changed the Ektapress 800, 1600, and 3200 films to Supra
800. Accordding to the tech sheets the film has been engineered for
better scanning.

Recently I used this film on a really overcast day. For some reason I
messed up my framing and had to use the computer to rescue the orders
that came in. I scanned the pictures at 890%; 300 dpi and then
applied the unsharp mask at A-6-; R-1.0; T-5. the results were a
pretty good illusion of sharpness.

I also recently had a costumer return a print I had enhance because
it was too grainy. The picture was shot on 800 speed film pushed to
1600. The mistake I made was to set the amount too high when I
unsharpened. Not only did the picture look grainy. ther was a color
shift in the grey horse that gave it a blue twinge.

Now an aside for Dan regarding layers and file size. I learned a
couple of tricks the other day when I was working on a image with
about 16-18 layers. the first problem I encountered was trying to
save and then re-open the file. I only have 300 megs free on my hard
drive so I crashed.

So to work around these problems I merged down what layers I could.
Then after I saved I turned off all the layers but the background.
Then when I closed I had a smaller file that was easier to open and
all I had to do was turn the layers back on.

Gary Owens


Dans Book

Dan Margulis <76270.1033@...>
 

Todd writes,

Dan, when you show the CMYK color values with an image, what part of the
image are they referring to? To my fairly newbie eyes it doesn't always
seem
to be the area under the icon, or am I wrong about that?>>

It's not supposed to be the area below the icon. The icon just illustrates
one of the key colors of the image, and how it changes as a result of the
correction. The idea is to get readers accustomed to what certain CMYK
values produce.

Dan Margulis


Re: Color settings and upgrades

Bob Smith <rmsmith@...>
 

Chris Murphy wrote:

You want a new computer anyway. Anything you get today will come with Mac
OS 9, and run Photoshop 6 so much faster than the 7100 making it worth
it.
Just for example... I've spent the last couple of days moving from an aging
and heavily upgraded 7600 to a G4 with twin 450's. A 120MB CMYK layered
Photoshop file opened in 1 minute, 40 seconds on the G3 powered 7600. It
opens in a little under a minute on my 400mhz G3 Powerbook. It opens in 6
seconds on the G4. That's a pretty damn serious performance improvement for
about $2500.

Bob Smith


Dans Book

tflash <tflash@...>
 

Hi Folks,

I'm very new to this list and am just beginning the PS 6 book. So far I love
it - just up to chapter three. I feel very fortunate to find this list too.

Dan, when you show the CMYK color values with an image, what part of the
image are they referring to? To my fairly newbie eyes it doesn't always seem
to be the area under the icon, or am I wrong about that?

Todd


Color settings and upgrades

Dan Margulis <76270.1033@...>
 

Gary writes,

I just upgraded my Mac to OS 8.1 (I've hesitated upgrading to 8.6 and 9.0
because I read that there were conflicts with Photoshop). I have both 5.0
and 5.5 in the computer and have set them to emulate the color settings for
Photoshop 4.0. If I calibrate my monitor with Colorsync will I have a
conflict with my photoshop settings?>>

No, but your images won't look the way they used to on screen, if that
upsets you. That's true for PS 4 as well as PS 5. The program's
calculations aren't affected by what you may do to calibrate the monitor.

I've just read Mr. Margulis article in the December 2000 issue of
Electronic Publishing about upgrades. I would like to upgrade to
photoshop 6.0 but as I mentioned before I'm still operating on 8.1
and if I would upgrade to 9.0 come January it will be time to upgrade
to OS X. I'm running a 7100/80 Mac.>>

I think with a box that old your decision to avoid 8.5 and up is a smart
one. That rules out the use of Photoshop 6. When you buy a new Mac, then
you'll have a new OS, and you can decide where to take it from there.

Dan Margulis


Re: Dan's "Black Hole" image

Ron Bean <rbean@...>
 

Dan Margulis <76270.1033@compuserve.com> writes:

I'd like to see reviews of digital cameras (either in print or on
the web) that use images as challenging as this one.>>

Good luck. First of all, the technology is improving so rapidly that almost
any review is obsolete by the time it appears.
That's why I suggested a website.

Second, you don't often see
reviews of either cameras or scanners written by people who are
particularly knowledgeable about the subject.
True, but it only takes one...

Third, few if any reviewers
see these cheap digitals as the revolution that they are, and the rest
insist on comparing them to previous film-based products.
Well, there are a couple of magazines devoted to consumer-level
digital cameras, and they don't give a flip about film.
The photos they've published in the past aren't that impressive,
but that could change as the technology improves-- especially if
a few of them would read your book...


Color settings and upgrades

gowens01@...
 

I'll start with a question. I just upgraded my Mac to OS 8.1 (I've
hesitated upgrading to 8.6 and 9.0 because I read that there were
conflicts with Photoshop). I have both 5.0 and 5.5 in the computer
and have set them to emulate the color settings for Photoshop 4.0. If
I calibrate my monitor with Colorsync will I have a conflict with my
photoshop settings?

I've just read Mr. Margulis article in the December 2000 issue of
Electronic Publishing about upgrades. I would like to upgrade to
photoshop 6.0 but as I mentioned before I'm still operating on 8.1
and if I would upgrade to 9.0 come January it will be time to upgrade
to OS X. I'm running a 7100/80 Mac. I will have to buy a new computer
to use OS X. And if I upgrade to Photshop 6.0 it will not be native
to OS X. And Photoshop hasn't said anything about a native upgrade
for OS X.

Thank you for your articles in Electronic Publishing Mr. Margulis. I
did follow your instructions to get Photoshop 5.0 to emulate the 4.0
color setting.

Gary Owens


Dan's "Black Hole" image

Dan Margulis <76270.1033@...>
 

Ron writes,

I finally got a chance to see the digital photo of the "black hole" that
appears in Professional Photoshop 6. Interestingly, the "before" version
did *not* print as solid black-- if I hold the book at an angle to the
light (to avoid glare), I can actually see most of the detail that shows up
in the "after" version. It's very dark, but it's there.>>

Well, *something* has to be there; even I can't fix an image that's 0,0,0
throughout. But I thought that the result when the range was opened up was
astonishing. I expected it to be full of noise. In fact, the result was a
lot better than one would get with a drum scan of a similarly dark piece of
a film--the scanner would have latched onto the film grain.

That particular image really should give pause to people who are obsessed
with extra bits. It's quality, not quantity, of data, that counts. That
corrected image can be expressed in 5 bits per channel.

Could the original have been improved by using a longer exposure?
(And maybe a tripod to keep the camera steady?)>>

Certainly, but that wasn't the point of the exercise, which was to get
something nearly hopelessly black and see what was actually there.

I'd like to see reviews of digital cameras (either in print or on
the web) that use images as challenging as this one.>>

Good luck. First of all, the technology is improving so rapidly that almost
any review is obsolete by the time it appears. Second, you don't often see
reviews of either cameras or scanners written by people who are
particularly knowledgeable about the subject. Third, few if any reviewers
see these cheap digitals as the revolution that they are, and the rest
insist on comparing them to previous film-based products.

Dan Margulis


Dan's "Black Hole" image

Ron Bean <rbean@...>
 

I finally got a chance to see the digital photo of the "black
hole" that appears in Professional Photoshop 6. Interestingly,
the "before" version did *not* print as solid black-- if I hold
the book at an angle to the light (to avoid glare), I can
actually see most of the detail that shows up in the "after"
version. It's very dark, but it's there.

Could the original have been improved by using a longer exposure?
(And maybe a tripod to keep the camera steady?)

I'd like to see reviews of digital cameras (either in print or on
the web) that use images as challenging as this one.


List FAQ

Dan Margulis <76270.1033@...>
 

Folks,

We've gotten several requests for an Applied Color Theory list FAQ.
Sterling and I have agreed on the following as a start. We'll probably post
it monthly. Like any other FAQ, it will change, so comments and suggestions
are welcome--nothing's set in stone. If you'd like to comment, please do so
to me or to Sterling privately.

Dan Margulis

Frequently Asked Questions--Applied Color Theory list

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Last revised: 12/13/00


Re: Dan Margulis MADE me rad the User guide

jonathan clymer <jeclymer@...>
 

psthree@aol.com wrote:

In Dan's most recent Makeready column there is a screen shot of a repositon
and resize. I wanted to know where its was so bad, i ripped the shrink wrap
off the user guide and tried to look it up!
i rad this three times and couldn't figure it out! Is there an editor in the
house?

Jonathan Clymer


Dan Margulis MADE me rad the User guide

psthree@...
 

In Dan's most recent Makeready column there is a screen shot of a repositon
and resize. I wanted to know where its was so bad, i ripped the shrink wrap
off the user guide and tried to look it up!


Re: Unsharp Masking at 50%?

Russell Proulx
 

On 19 Dec 2000, at 9:49, Dan Margulis wrote:

Russell writes,
what's wrong with making USM
decisions based on viewing at 50%?
You would then be looking at a crude RGB downsample to predict a very
complicated CMYK averaging process....

...While 50% is probably better than 66.7%, 100% is much better, but far
from perfect.

The above goes for sharpening/graininess issues only, obviously, not
for overall color evaluation.

Dan Margulis

Sigh....ok then. I was hoping for a better approach than guessing how
much "too much" is enough.

Russell Proulx
Photographer
Montreal, CANADA


Unsharp Masking at 50%?

Dan Margulis <76270.1033@...>
 

Russell writes,


<<I realize that it's generally recommended to perform Unsharp Masking with
an image viewed at 100%. But if the image's resolution is 2x the screen
frequency (for offset) then what's wrong with making USM decisions based on
viewing at 50%?>>

You would then be looking at a crude RGB downsample to predict a very
complicated CMYK averaging process.

When you ask for a screen preview at 50% you ask Photoshop to present a
preview where one screen pixel is based on an average of the RGB values of
four actual pixels. This is loosely similar to what would happen in print,
where each dot is produced from, approximately, an average of four pixels.
However, it's quite inaccurate, because,

1) In print the averaging is done per channel whereas on screen it's done
in composite mode;

2) On screen we are likely to see brighter colors as a result of the RGB
averaging, causing us to believe that the image has been oversharpened;

3) On screen the RGB averaging is likely to suppress mild patterns of noise
that would be visible in print, especially if they occur in the black
channel, causing us to believe that an oversharpened image is OK;

4) Any kind of monitor preview is going to be deceptive because it hits our
eyes with continuous color, as opposed to print, where the white space
between the dots has a significant softening effect. That deceptiveness is
magnified at a lower resolution.

While 50% is probably better than 66.7%, 100% is much better, but far from
perfect.

The above goes for sharpening/graininess issues only, obviously, not for
overall color evaluation.

Dan Margulis


Monitor Profiles

Dave Badger <dbadge@...>
 

I've been spending days trying to figure out why my previews in PS6 don't
match my previews in PS5 despite loading identical RGB & CMYK working spaces
and making sure I was viewing untagged files so they would we forced to use
those working spaces and not any embedded profiles within them. It didn't
matter which set of working spaces I used. The relative differences were
always there; the PS6 preview was significantly more saturated. I did a
RGB>CMYK conversion of the same file through both versions and ran it to the
Iris; they were identical and confirmed the PS5 preview was correct. (Along
with the numerical values).

I then went back to PS5 and started switching my ColorSync profile between
ColorMatch RGB, Abobe 98, and Wide Gamut. The preview changed; which makes
sense as your telling PS5 to run the color through different monitor
profiles which should change they way they look. There was no change
toggling between "ColorMatch RGB", "Pressview XL", and "Display Pressview
XL". I figured this was because all are generate by the Pressview
calibrating software and are identical profiles. (?)

I then went back to PS6 and ran the same experiment. But this time there was
no change in preview regardless of which profile I pick in the ColorSync
control panel (v 2.6.1).Only if I went to View and picked "Monitor RGB" in
the proofing list, did it matched PS5 (This is only available with RGB
subjects opened). This tells me maybe PS6 is not getting its monitor profile
from the ColorSync control panel. So I opened the Monitor Control Panels and
switched it from "Pressview XL" to "ColorMatch RGB" and while the display
lightened a bit, the previews now match.

1) I thought I read that PS6 was compatible with ColorSync 2.6.1 & OS 8.6,
but is it picking the monitor profile through the Monitors Control Panel as
if it was using ColorSync 3? If so, it seems to be ignoring the system
profile I choose in ColorSync.

2) ColorSync 3 would not install; is it compatible with OS 9 only?

3) What is the difference between "ColorMatch RGB", "Pressview XL", and
"Display Pressview XL" AND the "ColorMatch RGB" installed by PS. (Two
"ColorMatch RGB"s show up in both control panels.)

This is not a problem unique to Pressview as I went to my LaCie calibrated
with OptiCal and changed the Monitors Control Panel from "electra22" to
"LaCie 12/8/00" (My latest OptiCal profile) and solved the same problem
described above.


Dave Badger


Unsharp Masking at 50%?

Russell Proulx
 

I realize that it's generally recommended to perform Unsharp Masking with
an image viewed at 100%. But if the image's resolution is 2x the screen
frequency (for offset) then what's wrong with making USM decisions
based on viewing at 50%? Even Dan's most recent version of Professional
Photoshop leaves this issue ambiguous, admitting that the amount
required at 100% viewing is generally less than what the printed image
requires. Wouldn't judging the appropriate amount while viewing the image
@ 50% (with a very good monitor) be a better workaround?

Russell Proulx
Photographer
Montreal, CANADA


Re: Need help with web press cmyk

Dan Margulis <76270.1033@...>
 

John Sweeney writes:

<<If the plates are "curved" at the CTP device (that is, non-linear), is
the color bar being changed ? For example, if the color bar has a nominal
50%, BUT is curved to 52%, (in this example, weight added to CTP curves to
closer match conventional) then we are understating the dot gain, if the
assumption is the original was 50%.>>

A solid color bar won't change, but semisaturated colors certainly
will--they'll get dirtier. It's OK to adjust the color settings of a
digital proofer to chase another output device, or with the color settings
of a monitor to chase a proof. Trying to adjust a press to chase another
press is considerably more difficult.

Dan Margulis


Re: SWOP ink limit

Dave Balderstone <dave.balderstone@...>
 

At 1:36 PM -0500 12/13/00, Dan Margulis wrote:
So, I think the request for 280 is to make it more palatable when the
printer rejects 305. In practice nobody is going to reject for 300 for a
magazine printed on coated stock.
We've run 300 on newsprint if we've had to, even though our spec is 240. We've even run higher than that on occasion after the agency has been informed, has told us they can't get new material to us in time, and has accepted that color is going to shift when the press crew works their magic. But you've seen our operation, and I'm sure little we do would surprise you. <s>

Since acquiring our newest scanner a couple of years ago, though, we prefer to scan the film, descreen, then re-separate.

Dave Balderstone
Director, Technical Services
Western Producer Publications, Saskatoon, Canada


Re: what would cause this

Preston Earle <PEarle@...>
 

Chris writes:
So the explanations for why the proof isn't predicting this might be:

2.) Perhaps printing K first is factor contributing to excessive black
ink gain compared to what the proof is predicting.

Preston responds:

I don't believe the order of the ink laydown will have a significant effect
on dot gain. It could well have an effect on ink trapping, which could
effect the final print appearance. Normally, black is printed as the first
down color because it is usually the lightest form and thus gives fewer
problems with wet-ink trap.

3.) A laminate proof allows 400% ink and can still retain detail; unlike
a press. The shadow area needs to be lightened in order to reproduce
effectively on press.
As to the laminate proof, what kind of proof is it? Was it made from film
(Matchprint, Color-art, Waterproof)? In that case, it should have the same
dot characteristics as the image on the plate: Total ink limit, maximum
black, etc. The problems in not matching the proof would be in the press
or platemaking. If the proof was a digital proof (Iris, Approval, etc.),
wouldn't it have been made from the same CMYK file as the film/plate, such
that it showed the same separation characteristics as the printing
film/plate? The fact that it might show more detail for a 400%TAC file is
not relevant since the file from which it was made should have the same dot
values as the printing film/plate.

If the proof was from some other proofer, perhaps one that used an RGB
file, then certainly the color separation issues of RGB > CMYK could cause
the printed image not to match the proof, but wouldn't this simply indicate
that the "proof" wasn't really a "Proof", but rather a different
representation of the same image?

So this is one of those examples of the limitations
of these kinds of proofs. Interaction between inks (such as tack and
print sequence) is not predicted with pretty much any kind of proof
except a press proof.
Pre-press proofs should predict the interaction of the various elements
under "standard conditions". It's when the conditions fall outside
standard that a press proof might be required.

This isn't to say that the solution to making the printed image better
isn't in the RGB>CMYK conversion. As Dan points out, different images may
need different set-ups. However, if you adjust the conversion to take into
account the abnormal dot-gain due the particular print conditions, then the
proof won't match the original, but that's a different problem.



------------------------------------------------------------
I've tasted watermelons honestly come by, and I've tasted watermelons
acquired by art. Both taste good, but the experienced man knows which is
better.--Mark Twain


Re: SWOP ink limit

Dan Margulis <76270.1033@...>
 

Several people have queried what the SWOP standard is for total ink, what
the reasoning for the limit is, and how strictly it is enforced.

SWOP calls for a maximum ink limit of 300% in any area of significant size
and 325% in tinier areas. The reason for the limit is to prevent drying
problems, poor ink trapping, and possible ink contamination.

Most magazines knock this limit down to 280%. AFAIK, the reason they do so
is for bargaining room in case the printer rejects the film. Most magazine
prepress houses and printers offer SWOP ad inspection as a service. At the
time I was active in the field the inspectors were looking for an area the
size of a dime or bigger, in which the total ink was 305 or higher. They
ignored smaller areas altogether.

So, I think the request for 280 is to make it more palatable when the
printer rejects 305. In practice nobody is going to reject for 300 for a
magazine printed on coated stock.

Dan Margulis

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