Developing E-6 film as a color NEGATIVE

[Prof_Pixel]

You should stop using the word "mask". It may be orange but is not a mask in the true sense of the word.

That's right!!!!!! It seems no one has bothered to read my link in my message #16 in this thread that explains what the Kodak orange color mask is.

 

[David Lyga]

RPC and Professor Pixel:

Semantically, you both just might be correct, but I do not know for sure.

Actually, what is the precise definition of 'mask' as applied to photography? This is an interesting quandary that you have brought up. I naively thought that a mask was simply a 'screen' that could impart overall color or, really, anything else. Inform us. I know that the reason for the orange is to correct the hues (blue?) which could not be fully corrected with the couplers.

(And with Professor Pixel living right next to Kodak in Rochester, he just might know something!) Of course, both of you, I do not think that I am the first to use the word in this way, but, nevertheless, I wish to be correct. - David Lyga

 

[Mike Wilde]

I have optically printed cross procesed e-6 film normally processed in c-41 home brew, with the ferricyanide /bromide bleach under discussion.

When printing, I still project though a sandwich section of unexposed and processed c-41 film to provide the correct mask to tie to the dye sets in the ra-4 paper I am printing to.

Then you pick which colour in the print you want to be realistic ( if any) with your enlarger light source filtration and let the other hues distort as they are want to do in this process.

 

[Prof_Pixel]

When printing, I still project though a sandwich section of unexposed and processed c-41 film to provide the correct mask to tie to the dye sets in the ra-4 paper I am printing to.

In this case, the processed film simply acts as a color filter, not as a color correcting mask

 

[RPC]

In a nutshell, a description of a color negative mask is as follows: when the dyes are formed in a color negative, they have impurities (unwanted color absorptions) which taint their color. Collectively, these impurities form a negative orangish image (along with the regular dye image). Residual dye coupler, that which does not convert to dye during development, remains and forms a positive orangish image. It is orangish because the dye coupler was given that color during manufacture. The two images cancel one another. The dye impurity image thus has been "masked" by the dye coupler image. What results is a uniform orange color all over the negative, consisting of the mask (positive orangish image formed by residual dye coupler), and what it is masking, dye impurities (forming a negative orangish image). This uniform orange color is simply filtered out during printing and along with it goes the effects of the mask and the dye impurities, resulting in improved color in the print.

 

[Prof_Pixel]

Yup

 

[StoneNYC]

Question, is the orange "hue" in C-41 necessary if you are scanning?

In theory could they make a CN film without the orange color if you were only scanning? Without issues?


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[Prof_Pixel]

Question, is the orange "hue" in C-41 necessary if you are scanning?

In theory could they make a CN film without the orange color if you were only scanning? Without issues?

The orange 'hue' is there to correct for unwanted adsorption by dyes in the developed film. There have been color negative films that did not use such color masking (Agfa, for example). I believe the masking technology was in a Kodak patent.

So, yes, the color masking helps give better colors in both traditional printing and digital scanning.

 

[David Lyga]

Seriously, was Agfa so stupid? Perhaps not, with their 'clear' color negatives. I'll bet I could make a very nice print from a 'clear' color negative.

Maybe there was overkill here, maybe not: I am not versed in the finer point of 'hue', but, even with chromogenic materials, why all that damn density? - David Lyga

 

[Prof_Pixel]

, why all that damn density?

David,

Download http://motion.kodak.com/motion/uploadedFiles/US_plugins_acrobat_en_motion_education_H-188.pdf and read pages 40-43

(This is the Kodak Publication 'Color as Seen and Photographed' If you don't already have a copy, download it and add it to your reference library.)

 

[David Lyga]

Yes, roughly, the blue would be too prominent if the orange were not there to mitigate its effect. I already knew that, Professor Pixel, but what I am saying is this: Isn't the R&D at Agfa inhabited by people who studied this color theory? (Or, would you take the argument that that R&D there is inhibited by those very people!!!)

I do think that the folks at Agfa had a pretty good hold on color theory and that this was not a 'mistake' on their collective part. I am wondering if there was a trade-off in that, technically, you theoretically need the orange mask but could also get good color without?

Honestly, I do not know, but I don't think that the mask-less product delivered by Agfa has to be construed as an exercise in ignorance. There has to be a 'side' to their argument that held water. Correct me if I am wrong. - David Lyga

 

[Prof_Pixel]

I do think that the folks at Agfa had a pretty good hold on color theory and that this was not a 'mistake' on their collective part. I am wondering if there was a trade-off in that, technically, you theoretically need the orange mask but could also get good color without?

The use of color masking couplers was a Kodak patent. I certainly can't speak for Agfa, but they may have used another approach.

See AgX's discussion of masking in (there was a url link here which no longer exists)

 

[RPC]

The lack of a mask is a reason prints from reversal films have never had the color quality of prints from color negatives. This has been mentioned many times in this forum by PE and others. I have printed slides onto Cibachrome and observed this myself, and to many experienced printers it is common knowledge.

On the subject of Agfa color negatives, I refer to Bertram Miller, an experienced color printer and researcher who wrote articles on color printing for Darkroom and Creative Camera Techniques magazine and here is a excerpt from an article he wrote, "Color Reproduction in Negative Films":

"If these dyes didn't receive special treatment, the problems would be compounded in the prints. In fact, It was a serious problem for me when I began to print from unmasked Agfacolor CN-14 negatives many years ago. Thankfully, there are no surviving examples of the distorted and grayed-down colors I got then. Those who have no memory of those days will not believe the amount of orange the skin contained, nor the amount of purple in the skies."

After the masking technology was developed by Kodak to solve this problem, Agfa too, masked its films.

It is also true that today, specific dye-coupler types and inter-image effects also perform some of the needed color correction, but the mask still performs the bulk of it.

 

[Prof_Pixel]

RPC,

THanks for the information.

 

[StoneNYC]

The lack of a mask is a reason prints from reversal films have never had the color quality of prints from color negatives

You're saying that CN film has better colors in a print than cibichrome prints? I'm not sure how I can believe this when everyone talks about the amazing colors of Cibichrome prints, and all my views of CN prints on RA-4 are not as impressive. Can you show me examples?

 

[Prof_Pixel]

everyone talks about the amazing colors of Cibichrome prints, and all my views of CN prints on RA-4 are not as impressive.

Never confuse 'amazing colors' with 'accurate colors'. People seem to prefer saturated, higher contrast colors than actually exist in life.

 

[RPC]

Cibachrome prints do not have the color accuracy of prints from color negatives. Yes, the colors pop. But my Cibachrome prints never had the skin tone accuracy of CN prints, and skies, while not purple, often appeared a bit grayed-down. The later version of Cibachrome had a form of masking built into it, but it was not completely effective. CN prints can produce beautiful skin tones and skies, much more accurate to me. On the other hand I have produced prints from films like Ektar that nearly matched Cibachrome saturation-wise, but with better color. Kodachrome is another case where people liked its look, and perceived it to be accurate, but as PE has said it suffered from crossover and dye-impurity problems. People may like the look of an image but that doesn't mean it is accurate.

 

[MattKing]

Never confuse 'amazing colors' with 'accurate colors'. People seem to prefer saturated, higher contrast colors than actually exist in life.

+1!!!!

 

[StoneNYC]

The way it was phrased it sounded like you meant chrome prints were dull...

And yes, I find "accurate" color to be inaccurate to my eye, I've even taken a picture on c-41 and then went back a day later, the colors ARE dull and don't show what my eye does.

Not as much as E-6 of course, but more than C-41

Anyway thanks for answering my query.


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[David Lyga]

Thank you Professor Pixel for that information. This field is truly dynamic: nothing stays still.

PE said in January 2009: "A filter is uniform in density but a color mask has varying density that is inversely proportional to the image".

That is true and I confirm: if you look at lower densities on your color negatives you will see NO orange in that part because 'another color took its place' even if that other color has a lower overall density as compared to the orange.

STONE: never forget that the color you view those photos in can impart mighty differences in perception. Fluorescent is the worst. K3400 the absolute best. (These are my lifelong experiences and might not speak for all.) And when you find accurate color to be inaccurate to your eye perhaps you really mean 'unacceptable' to your eye. Yes? As RPC said (through PE): (mighty) Kodachrome suffered from inaccuracies in hue and crossover BUT.....BUT....was ACCEPTED as perfect by the public!

And thanks, RPC for bringing us up to date on the remission Agfa decided upon in order to atone for its 'maskless' sins. Apparently, they learned, albeit a bit late. I'll bet they wanted a simpler approach that might have been plausible in theory but maybe not in practice. I am still intrigued as to unfolding the complete story because Agfa is not exactly a 'fly by night' manufacturer. Their theoretical basis must have held water.

- David Lyga

 

[StoneNYC]

True David, though I tested by daylight (the sun) lol


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[RPC]

PE said in January 2009: "A filter is uniform in density but a color mask has varying density that is inversely proportional to the image".

That is true and I confirm: if you look at lower densities on your color negatives you will see NO orange in that part because 'another color took its place' even if that other color has a lower overall density as compared to the orange.

In all the color negatives I have ever seen even the low density areas and clear areas have orange.

Yes, the mask does vary in density as PE says.

But to make sure there is no misunderstanding, if you refer back to what I wrote earlier, the orange color on a negative consists of TWO things, the mask, AND what it is masking, dye impurities. The former forms a positive orange image, and the latter a negative orange image. Together, they form no image at all, just a UNIFORM orange all over the film which is filtered out in printing. Even the clear areas are orange, because there is residual dye-coupler there.

So If someone says the orange color on a color negative is the mask, that is incorrect. It is the mask, PLUS what it is masking, and it is uniform.

 

[David Lyga]

RPC, I have seen negatives that have LOWER overall density in the shadows than in the edge of the negative where there is no exposure, only orange. - David Lyga

 

[RPC]

RPC, I have seen negatives that have LOWER overall density in the shadows than in the edge of the negative where there is no exposure, only orange. - David Lyga

I have looked at quite a few of my negatives and could not see anywhere what you described. Think about it-if the edges of the film receive no exposure, and produce a given density after processing, how can some point in the image, which also receives no exposure, be any different? If that point received even some exposure, it would then have more density. Perhaps spurious light is somehow slightly fogging the edges of the film in your camera?

As I recall, you process your film in a non-standard process using RA-4 developer. I can't see how even that would cause what you see, but who knows.

 

[David Lyga]

RPC. in my case the low exposure parts seem to NEGATE (not add to) the orange (mask?). In other words, where ANY exposure density manifests, NO orange forms to 'add' to the density.

I would like corroboration or refutation here, as I am curious. - David Lyga