A couple of questions for color printing

[Shinnya]

Hi,

We finally started using the color darkroom! We did replace a lot of parts for CP-51, and that took some time since I had to oNow I can starting printing color images at our studio too.

I just have a couple of questions or regarding color printing. If you can answer or redirect me to appropriate sources, it would be great!

1) Why are we only using Y and M to do color correction. I know that is how it is done, but why we are not using cyan?

2) What does the orange cast on color negative do?

I just simply wondered about these things while I was in the darkroom...

Warmly,
Tsuyoshi

 

[Nick Zentena]

You could use Cyan and if the negative is really out of whack you might have to. I think additive printing normally uses it but I forget. Cyan is like using both M&Y.

 

[Photo Engineer]

You use M and Y for 2 reasons. The first is that the paper has the yellow layer on the bottom and the M and Y supply color separation from the blue speed of the C layer. The second is for simplicity and for proper balance of daylight negatives to the enlarger bulb.

The orange color is a mask that forms a positive dye image during processing that corrects for the unwanted absorptions of the cyan and magenta dyes.

PE

 

[Neal]

Dear Tsuyoshi,

The reason you only use 2 of 3 filters is that if you used all three that would be the same as a neutral density filter. Cyan is used with magenta when printing slides (Ilfochrome is the only system left for direct printing of slides.).

Enjoy your printing.

Neal Wydra

 

[nworth]

Color papers are crafted to avoid the need for using cyan filters. Life is simpler when you only need to adjust two filter values. Some reversal color papers that used to be available had a neutral color balance and occassionally needed cyan correction. That is seldom needed with color negative film.

 

[Ed Sukach]

I just have a couple of questions or regarding color printing. If you can answer or redirect me to appropriate sources, it would be great!

1) Why are we only using Y and M to do color correction. I know that is how it is done, but why we are not using cyan?

2) What does the orange cast on color negative do?

Answers to both 1 and 2: The "orange cast" on the negative is really saturated yellow, a.k.a. "brown". It is there so that, for most of our negatives, we don't have to use a Cyan filter - remember that we are printing negatives, so yellow on the negative winds up as cyan (opposite color) on the print. It acts as a preset amount of color filtration.

At times the amount of built-in "yellow" filtration is too much (as when mixed, or different color temperature illumination than the film is `balanced for' is used in exposure of the negative) ... so for balance it is necessary to add cyan - in effect, subtracting yellow.

Careful - even as I write this, I tend to get confused. Remember that "yellow" filtration will cause cyan on the print.

 

[Photo Engineer]

Ed;

Here is an example of the major reason for the orange cast.

I repeat. The orange mask is a posiitive image that corrects for the unwanted absorption of the magenta and cyan dyes. It is therefore the opposite color or in this case orange.

It has other purposes but was first introduced by W. T. Hanso and P. W. Vittum of Eastman Kodak.

The example shows a positive image and a negative image that cancel the blue absorption of the cyan dye making it purer for better color reproduction.

PE

 

[Ed Sukach]

PE,

Ooops...!

I did not realize that I was disagreeing! Believe me, I usually would give the question a HELL of a greater amount of thought than I did here, before I would disagree with you.

I've read your last message a couple - or three times. I think I have a vague idea of what it means. I stand corrected, I guess.

On a simpler, hands on in the darkroom level ... was I terribly misleading?

 

[TheFlyingCamera]

Answers to both 1 and 2: The "orange cast" on the negative is really saturated yellow, a.k.a. "brown". It is there so that, for most of our negatives, we don't have to use a Cyan filter - remember that we are printing negatives, so yellow on the negative winds up as cyan (opposite color) on the print. It acts as a preset amount of color filtration.

At times the amount of built-in "yellow" filtration is too much (as when mixed, or different color temperature illumination than the film is `balanced for' is used in exposure of the negative) ... so for balance it is necessary to add cyan - in effect, subtracting yellow.

Careful - even as I write this, I tend to get confused. Remember that "yellow" filtration will cause cyan on the print.

Ed-

just to clarify something else in your post:

adjusting the yellow filtration will adjust the color balance along the yellow/blue axis. Adjusting the Magenta will adjust along the magenta/green axis. Cyan affects the red/cyan axis. If a print is too cyan, you add magenta and yellow, or subtract cyan. If it is too yellow, you subtract yellow. If it is too red, add cyan, or you subtract magenta and yellow. And so on. The above is assuming you are doing printing from negatives.

 

[Photo Engineer]

Ed;

Your answer was fine, just a little vague on the reasons.

Scott;

Your answer is backwards. If a print is too yellow, add yellow, if it is too magenta, add magenta and if it is too cyan take out magenta and yellow.

The blue sensitive emulsion forms yellow dye. If the print is yellow, you must subtract blue speed by adding yellow filtration. I know it is counter intuitive, but that is the way it works.

You were talking from the aspect of a reversal print material and were correct, but not for color negative printing.

Another way to look at this is this fact... The red layer (cyan dye forming layer) is the anchor point for speed. So, you don't want to affect the red layer by adding cyan filtration and affecting the total speed of the paper. This is another way of looking at what Ed said.

PE

 

[Mick Fagan]

PE, I understand that the red colour is obtained by density, as in, more exposure, more red, less exposure, less red.

Obviously this works correctly when the M and Y filtration are correct.

Mick.

 

[gbroadbridge]

Ed;

Your answer was fine, just a little vague on the reasons.
PE

You guys are making things way too complicated

I typically do a single test strip to determine exposure and then just use my old fashioned "Kodak color print viewing filter kit" (Publication No R-25), follow the instructions and do what it says.

Normally I end up with a perfect 8x10 print every time

Graham.