ColorPos and ColorNeg Why and How: The Short Version
This was written fairly early in my research on color integrity, around 2007, and remains here for continuity. Looking through it I find little that I would disagree with today.
Now and then in the various photography forums I find discussions of these web pages. Here I will try to clarify some of the what and why about my pages on color photography.
Color Integrity - The Basic Problem
All of this was started by my observation that there is a tendency for digitally produced color images to have poor color. Perhaps "unsettling" color would be more accurate. Before you write this off as ridiculous, I urge you to check it out. The easiest way is to compare similar sets of professionally produced color photographic images from pre-digital days, say 15 years ago or earlier, with sets produced today. Look at issues of the same magazine then and now, the ads as well as the features. If you have access to good color prints from both eras - perhaps your own or a colleague's - compare then and now. I am by no means saying that all photographic images produced now have poor color. Far from it. Likewise, not all photographic images produced then had good color. I don't even claim that you will find the effect in all magazines. I am saying that the effect is common enough that if you actually make an effort to look for it you will find it. Once you understand what it is, you will start to see it "everywhere."
Note that you can verify this phenomenon for yourself, independent of anything I say and independent of the mathematics and physics in my web pages. The effect you are looking for is difficult to express in words. There is a clarity of color present in most quality older color photographic images that is missing in many current ones. The colors in the current images may be more intense but at the same time somehow lack depth - I generally say "murky," though that is an inexact description. I believe that many photographers are aware of this at some level, just as I was two or three years ago, reasonably satisfied with their work, but with a feeling that something is "off" somehow. [One easily accessible example is the National Geographic magazine. I was just looking at the October, 2006 issue which has a number of examples that give the unsettling effect, and examples are also common in other recent issues I have checked. Compare with a National Geographic from the early 1980s or earlier, probably available at your library. Easier, take a look at the January, 2007 issue of Popular Photography, the picture contest issue. Many of the winning photos and even the photos in articles suffer from the murky color effect I describe. There are, however, some notable exceptions which you should easily be able to pick out for comparison. ] I think that attempts to disguise this unsettling effect have led to some of the more common "artistic" effects currently seen.
Color Integrity and Color Balance
My studies into this phenomenon led to the concept of "color integrity." Color integrity is a concept completely separate from color balance. "Color balance" is an effect resulting from differences in lighting and can be corrected using colored filters. If an image is "too green" you can fix that by adding magenta or subtracting green through filtration. Color integrity is achieved by calibrating the image acquisition system so that the light intensity values represented in the digital image are proportional to the light intensity values in the source for the image. As such it is a matter of calibration. See my web page on Color Balance and Calibration for a more detailed explanation of the difference between color balance and calibration and a rather different discussion of color temperature as well. An image can be way off in color balance and still have color integrity. If an image has color integrity all that is required is to apply the proper colored filter and the color balance will be "perfect." An image without color integrity cannot be correctly color balanced no matter what color correction filter is applied and that is the root of the unsettling color you see. The color balance varies from place to place and from dark to light in the unsettling images. The mind's eye quarrels with this confusion.
Color balance has an element of esthetic taste. A group of photographers viewing the same good photograph will almost always disagree on whether it is properly color balanced and exactly what is wrong with it. I like to reflect on an incident many years ago when I had entered a color print in a local show. My print not only did not win, it was rejected. One of the judges was a prominent local photographer and I asked him why. "The color balance is too far off for us to display the print."
To my mind the color balance was dead on. I asked, "Just how is the color balance off?"
"Well," the judge said, "Just look at the little white flowers. See how they all have a very blue cast to them?"
"Oh," I said, "You mean the bluettes??"
To see more clearly what I mean about color integrity and color balance, look at my web page on Color Integrity.
Can Photoshop Be Wrong?
OK, so if there is a widespread color integrity problem, how did this come about? "Photoshop is the accepted standard. It can't be wrong!"
As I will touch upon a bit later, Photoshop can indeed be wrong, but errors in Photoshop are not the source of the main problem. The problem comes about because the design of Photoshop ignores some very basic properties of RGB and CMY three primary color systems. This is most easily seen in that Photoshop has no mention of CC (Color Compensation) filters, the basic element in color photography. In my web page on Dunthorn Calibration I extend quite plausible reasons why Photoshop developed in this non-photographic way.
In any event, the result is that most Photoshop training tends to aim the photographer at the wrong tools for making the initial, sometimes large adjustments of images from photographic sources and Photoshop itself makes doing the correct initial adjustment significantly more difficult than doing the wrong adjustment. To illustrate, one very common practice is to use the Levels tool to do a white balance, a black balance, and a middle-gray balance in order to "color balance" a photographic image. When using this procedure, anything you do beyond the initial so-called white balance is calibration rather than color balance. Calibration should characterize film and equipment and it is both unnecessary and undesirable to apply separate calibrations to each individual image. Understand, I am not saying that it is impossible to use this procedure to produce reasonable results. The process will work if the final middle-gray balance makes very little change in the image. But I am saying that if that final middle-gray balance makes a significant change in the image you are being fooled in precisely the way that causes the "murky" colors I describe above. See my Color Integrity page for an explanation of this without much math involvement. In fact, although you can make the correct color balance adjustment in Photoshop, it requires double sampling and entering numbers in between.
A Few Photoshop Errors
As to whether Photoshop has actual errors, in the course of sorting out the color integrity problem, I did indeed find a number of things that Photoshop does wrong. You will find comments on these sprinkled throughout my web pages and I have made no effort to collect them as a unit. As is the case with the color integrity problem, the areas Photoshop gets wrong normally stem from what are euphemistically called legacy effects. For example, the black point or shadows adjustment in Levels is done incorrectly because Photoshop traditionally has worked directly on "gamma-encoded" images using forms that are actually intended for linear images. While this incorrect treatment of the shadow adjustment does affect color even up into the mid-tones, it normally has a less drastic effect than the middle-gray adjustment part of the incorrect color balance procedure described above.
One place that Photoshop has it decidedly wrong is the Invert tool applied to photographic negatives. It is so wrong that one might have excused this on the basis that Invert may have been intended for other purposes. However, Adobe clearly shows their lack of understanding of the problem when their documentation says that Invert does not work well due to the orange mask which color negatives have. In fact, Invert gets the tonal scale all wrong even on black and white negatives that do not have such a mask. The orange mask presents no problem at all when color negatives are inverted correctly. Although my early web page presents a way you can deal with color negatives in Photoshop, it is very time consuming, the results are only marginally satisfactory, and it has serious problems in producing results with adequate color integrity. Consequently I wrote what turned out to be a series of plug-ins for Photoshop to deal with color negatives and color integrity in general.
One cannot place all the Photoshop problems and errors at the feet of "legacy," however. Photoshop RAW is a recent addition and it introduces some brand new misdirections. In one instance, however, RAW does correct an error still present in Photoshop proper. The shadow adjustment is done correctly in RAW. However, RAW prominently labels one of its controls brightness when in photographic terms it is nothing of the sort. In fact, the "Exposure" control is photographic brightness although it appears to do a little additional tweaking of the brightest areas of the image. The "brightness" control actually appears to be mostly a gamma adjustment of limited range with meaningless numbers applied to the scale. As "brightness" Adobe has made this control the most likely to be used and using it will destroy color integrity right from the start. Color balance reverts to an archaic color temperature - tint system that while inexplicable is also harmless - its effects can easily be corrected in Photoshop. Worst of all is the tab labeled "Calibrate." I can't go into the necessary detail here, so let me just say that the adjustments offered under this tab violate the mathematics and physics of digital camera calibration (specifically as regards degrees of freedom). Even as adjustments for an individual image they are a poor choice, being applied in a way that destroys color integrity.
If All This Is True, Why Are the Experts Not on Board?
The question arises: If there is anything to what I am saying, wouldn't the experts be all over it? Doesn't the fact that they are not prove I must be wrong?
That is not how it works. Any experienced innovator can tell you that there are four stages to an innovative idea such as this. In the first stage the innovator devises and describes the concept. The experts will assure you that it is wrong, considering it not even worth their time to actually check it out. In the second stage the innovator will provide some examples of how the concept works, such as I have done with the plug-ins and the above suggestions of how to observe the color integrity problem "in the wild." Here the experts will still assure you that it is wrong, but a few of them will start to check it out so that they can find an easy proof that it is wrong. The second stage, starting into the third stage is where we are now. In the third stage some of the experts start to find out that the concept really does seem to work, and they show it to other experts who also begin to use the concept. This is where the concept gains acceptance and usage starts to expand. In the fourth stage to concept is in use, the spread of which is consistent with its usefulness. At this stage if you ask the experts about it they will explain it in full detail and tell you that it is obvious and has always been obvious.
You photographers reading this, be aware that you are as much the experts as the development people at Adobe and elsewhere. See if the above paragraph does not apply to what you have observed.
How About the Money?
And the final question, at least for now: Don't I expect to make a lot of money out of this?
In a word, no. I am a realist. It takes a person who is a promoter as well as an innovator to make a lot of money from situations like this. There are very few such people and I am not one of them. If I ever even realize what might be considered just compensation for the time I have spent on this project I would be both pleased and very surprised. At some point this concept may get fully into stage three, where there is some hope of limited financial rewards. But then think what will happen when it passes from stage three to stage four. The color integrity and color negative inversion technology has been freely available on my web site and is now archived widely across the world. Adobe can incorporate it directly - and fairly easily - into Photoshop. If they don't do that there are dozens of other software suppliers all over the world ready to jump on the bandwagon and provide plug-ins or stand-alone programs with better features than mine and much better marketing and production skills. I could not effectively compete with that even if I had the desire, which I do not. So, no. Unless some minor miracle happens, at best I will realize a fair return and in all likelihood considerably less than that.
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