Re: synchronizing color - not really possible today -- Honey: Didn't you say MACs can solve this?

[David Neeley <dbneeley -at- oddpost -dot- com>]

Some years ago, a color enlarger was made which used additive color rather than subtractive. It had individual light streams for each color substrate of the photographic paper, with all the light filtered completely for each color. To add red, for example, the photographic darkroom technician merely dialed in extra red. None of the other colors were affected by the change in one of them at the color layer level, and attaining the most pleasing exposure was much faster and simpler working in the positive mode. 
  
Thus, in that case, the color model was geared to the actual color reproduction of the layers in the paper...and it did not work from a subtractive model from the standpoint of the enlarger...even though the result was being printed on photographic paper. In addition, the pure light colors eliminated much of the problems that stem from unfiltered light of various frequencies affecting the various color strata differently that always exists in conventional photographic enlargers using the CMY color model. 
  
>From the standpoint of screens today, backlit flat panel displays work much more similarly to this printing paper than do CRT displays. The light is not coming from the LCD crystals, but from a fluorescent light element behind them. I believe this could be implemented either using an additive or a subtractive color process, although I would have to consult some people more versed in electrochemistry than am I. However, in terms of engineering, this would be what I have called an "implementation detail." So far, the color flat screens have been built to mimic the color models of CRT screens, but that is not something that is necessarily engraved in stone if what I have been told by some of the engineers is to be believed. 
  
There are also other types of elements that can be activated by varying the electric field. Some of them can now be switched rapidly on or off, and are transparent when in one state and opaque in another. These are being devised for use in solid state "shutters" for cameras and for various other uses such as in windows for sun control or privacy. If there were a reason to do so, I maintain it is feasible to design screens with a variation of this technology in which the degree of obscuration could be controlled and the color likewise controlled. This could be the basis for a subtractive system in an LCD context. 
  
Then we have newer flatscreen technologies being rapidly developed, such as OLED screens that should become very prominent in computer monitors in the next several years. Since the individual color elements in these screens are themselves emitters, again we have a situation much more similar to the CRT technology in color production. 
  
The fact that a system could be built using differing technology and a different color model does not mean it could be switchable from one to another. I have not claimed such nor do I believe it is likely. 
  
Color primaries, too, are not fixed but are instead merely conventions. Just as the subtractive model is normally, as you have indicated, either BYR or CMY, any other combination of three colors could have been chosen so long as they are equidistant around the subtractive color wheel. The choice usually depends more upon the physical characteristics of the medium than anything else--and in offset lithography, as you know, the use of screens complicate the situation a great deal since there is not a complete overlap of the color regions but instead a highly colorful mix when seen under magnification. 
  
I am pleased to have been reminded that the various media work somewhat differently in terms of color. I appreciate the corrections offered! 
  
My principal point, however, was that it is not simply the RGB-CMYK conversion that is at play. Viewing color through the color medium with the light shining through it is more intense than viewing it on paper--again, simply recall the difference between color slides and color prints. The substrate may not even be adding any particular color to the reflection (in the case of a bright white paper, for example)--but it will still not be as intense as in the transmissive forms such as color slides or computer monitors. However, with the most advanced inkjet technologies, they are certainly coming very, very close! (Keep in mind, too, that "photo realistic" printing often involves six or more colors rather than the more limited CMYK model. The problem is not the physics, of course, but the chemistry!). 
  
As for the Mac, its initial superiority in designing for four-color printing was that the operating system color model was from the beginning a four-color one. Unfortunately (from a printing perspective) it was not until various software vendors abandoned the Windows color system (RGB) and built their own into their products that the PC began to be truly competitive with the Mac. However, since the OS deals with this conversion in a standard way in the Mac, it is still much simpler to synchronize the Mac color so that the onscreen rendition is a close match to the printing device output. Unless you use a particular family of applications on the PC using the same color engine, it is not unusual for each one to be subtly different in color handling. Also, the fact that the Mac has traditionally been the platform of the printing profession, there remain more tools to handle all this simply...but of course that gap is diminishing rapidly. 
  
David 
  
  
  
-----Original Message from eric -dot- dunn -at- ca -dot- transport -dot- bombardier -dot- com----- 
  
David Neeley <dbneeley -at- oddpost -dot- com> wrote on 10/16/2003 12:38:10 PM: 
> Excuse me, but what does "light emitting device" or "light 
> reflecting device" have to do with the color model? 
  
Screen vs. Print colour will ALWAYS be an approximation. Pigments on paper 
absorb light, removing light/colour from the spectrum the viewer perceives. 
Phosphors on screens emit light/colour adding to the spectrum the user 
perceives. 

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