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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 mostTechnically 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 needsThe 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 moderateThe 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 thisExcellent! 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 PantoneOR 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 ofFor 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 anThey 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]
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Re: ICC profiles and digi-cam
Ron Bean <rbean@...>
Lee Varis <varis@...> writes:
White balance is like a profile in this sense:to which Andrew responded: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 andOK, I said "kind of like" not exactly like.. 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:"What the camera saw" is the raw CCD data, which is not affectedBecause again, the role of the profile isn1t to set or alter gray balance. 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.
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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: sure are neutrals (R=G=B is neutral in a Working Space). Input spaces can describe a neutralThere is no such thing as known values for skin tone. In RGB, the only numbers that are for 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). 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 cameraThere 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 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.
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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 totallyThere 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 skintonesThat 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 isThere 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 otherONLY 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 firstIF 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]
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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.
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Re: Digital Photo Conversion
Dan Margulis <76270.1033@...>
Kiki writes,
saturated enough.>>When I open HDR files in Colorshop some images are very weak and not 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. scanner before bringing the file into Photoshop for color correction. Am IIn the old model we could take a transparency and adjust color on the 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. I don't, except in comparison to, say, Adobe RGB for prepress destinations.It seems I recall Dan stating sRGB is a good mode to work in.>> 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. each portrait setting to know where my color is at, since my monitors areWould it be preferable to ask studios to provide a gray card shot wih 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
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Re: ICC profiles and digi-cam-last post
Hi again,
To be fair to Andrew I think I need to clarify a few things, I wrote: to which Andrew responded: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 andOK, 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: Andrew responds:Almost Because again, the role of the profile isn1t to set or alter gray balance.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: to which Andrew responds:Once this is done a camera file can be No! It will only insure you have a neutral gray. If what you say is true,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 theI 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 ifHere 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 I don't generally find it necessary to work with raw 16 bit data for most images. I wrote: Andrew responds:The benefits are not great enough to Depends on the camera and what the raw data is. Be my guest and assign anyAndrew 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... Andrew responds:For instance, if you manually white balance a sunset scene you will "balance No, input profiles don1t change the data, they only describe the data. IFOK, 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: Andrew responds:I think the challenge for photographers or anyone dealing with How do you interpret 11s and zero1s? That1s all a digital file is. That isWell... 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
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ICC profiles and digi-cam
Ron Kelly <abcolor@...>
Lee Varis wrote:
We can expect toMr. 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
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Re: Digital Photo Conversion
penneykid@...
You need to have a good calibrated monitor and then try out various colorFirst 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@...
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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 colorI 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 canNo, it¹s more like having a slew of profiles to reflect a slew of balances which is complicated and usually not necessary. AlmostBecause 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 beNo! 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 toDepends 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 "balanceNo, 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 withHow 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]
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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
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Re: ICC profiles and digi-cam
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".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 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 eachIt 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 allNothing 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
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Re: undocumented "features"
Dan Margulis <76270.1033@...>
Harold writes,
equipment. I find it so amazing that it is not possible to find addiquateDo you know of a source for any of the "undocumented features" of canon 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
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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 allIf 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
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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.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".
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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 enoughI¹m 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]
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Re: ICC profiles and digi-cam
Ron Bean <rbean@...>
DMargulis@... writes:
Just because white has been balanced doesn't mean that black hasTrue, 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. How time consuming is it to take one (1) extra shot with thetime and use th at to generate a source profile on the fly (IIt seems to me it would be better to shoot a color target each 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 areIn 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).
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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.
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Re: ICC profiles and digi-cam
Dan Margulis
Ron writes,
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.I've always wondered about this. Traditionally, photographers divided the universe into "daylight" and "tungsten", and this was considered sufficient (flourescents were considered hopeless).>> 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.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?>> 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.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).>> Dan Margulis
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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'llI'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?
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