Cyan setting on color enlarger?

bvy · Feb 16, 2017

Berri said:
Today I Printed a frame from a roll of kodak portra 400 exposed and processed at 1600. The frame was shot in the shade. I had to use 5C to get the colours right. The filter pack at the end was 40M 5C

Seems extreme but not impossible. The point is you dialed yellow down to zero and still had a blue cast. At which point, the only way to correct it would be to dial up cyan and magenta (=blue) in tandem.

I frequently print cross-processed Provia and occasionally have the same issue.

Photo Engineer · Feb 16, 2017

It could be due to the extreme push!

PE

wiltw · Feb 16, 2017

sidearm613 said:
I'm not sure if this is true, but I believe that you do sometimes have to touche the cyan dial when doing Cibachrome. But never with RA-4. Somebody more knowledgeable confirm that what I'm on about is true.

I printed Velvia on Cibachrome way back when...I just looked up my darkroom notes for a number of shots which I printed (a number of them 'mass produced' for Xmas print exchanges in a group of a couple dozen folks, so I needed to recreate filter packs for multiple printing sessions). Some shots had M only in the filter pack values I would dial into my Beseler Universal 45 color head controller; a number of shots had Y+M ; but a number of shots had M+C values. When there was any Cyan in the pack, it might be a value of 10C to 35C; and that in spite of the fact that the Cibachrome starting filter pack for a batch of paper said 15Y + 40M or 10Y + 35M.

As for printing color negs, my color neg printing in any volume was purely for portraiture or weddings and I always sent that work out to a lab oriented to professional needs. I never did sufficient printing of color negs for personal use to keep lab notes on filter packs.

Gerald C Koch · Feb 16, 2017

Cyan can be very useful if you are using VC contrast B&W paper. The paper is coated with a mixture of two or three emulsions. One emulsion is sensitive to blue light and the other to green. By exposing the paper first to blue light and then to green any paper grade from 0 to 5 is theoretically possible. At one time this technique was very popular.

Berri · Feb 16, 2017

bvy said:
The point is you dialed yellow down to zero and still had a blue cast. At which point, the only way to correct it would be to dial up cyan and magenta (=blue) in tandem

that's right

Berri · Feb 16, 2017

This is the straight print, no dodge, no burning. Filter pack was 40M 5C.

bvy · Feb 16, 2017

Whatever does the job... Looks good to me.

cowanw · Feb 16, 2017

Gerald C Koch said:
Cyan can be very useful if you are using VC contrast B&W paper. The paper is coated with a mixture of two or three emulsions. One emulsion is sensitive to blue light and the other to green. By exposing the paper first to blue light and then to green any paper grade from 0 to 5 is theoretically possible. At one time this technique was very popular.

I don't understand how cyan is useful with VC contrast B&W paper.
Increasing or decreasing cyan changes the amount of red that is let through, which does nothing as the paper is insensitive to red. Whether the cyan is minimized or maximized it does not block any blue or green, so that moving the only cyan dial (with yellow and magenta at 0) has no effect and is the same as white light.
Exposing the paper to blue light is accomplished by 0 yellow filtration and max magenta filtration.
Exposing the paper to green light is accomplished by 0 magenta and max yellow filtration.
At least in a world of perfect filters.

Gerald C Koch · Feb 17, 2017

cowanw said:
I don't understand how cyan is useful with VC contrast B&W paper.
Increasing or decreasing cyan changes the amount of red that is let through, which does nothing as the paper is insensitive to red. Whether the cyan is minimized or maximized it does not block any blue or green, so that moving the only cyan dial (with yellow and magenta at 0) has no effect and is the same as white light.
Exposing the paper to blue light is accomplished by 0 yellow filtration and max magenta filtration.
Exposing the paper to green light is accomplished by 0 magenta and max yellow filtration.
At least in a world of perfect filters.

Look at the color wheel.

Cyan + Yellow = Green
Cyan + Magenta = Blue

You therefor have the two colors that the VC paper is sensitive to. At one time enlargers for VC paper contained two cold light sources a blue one and a green one. The paper was exposed twice once with blue and once with green light to produce the desired contrast.

RPC · Feb 17, 2017

Using a color enlarger in this manner to make VC paper exposures seems a bit cumbersome and problematic, though.

Using the yellow control to adjust the blue, and the magenta control to adjust the green is the simple, usual way.

chrisaisenbrey · Feb 17, 2017

Gerald C Koch said:
Look at the color wheel.

Cyan + Yellow = Green
Cyan + Magenta = Blue

You therefor have the two colors that the VC paper is sensitive to. At one time enlargers for VC paper contained two cold light sources a blue one and a green one. The paper was exposed twice once with blue and once with green light to produce the desired contrast.

All true but VC paper is blind to red light.

Hence the VC paper can’t distinguish between yellow and green light and it can’t distinguish between magenta and blue light.

darkroommike · Feb 17, 2017

Gerald C Koch said:
Cyan can be very useful if you are using VC contrast B&W paper. The paper is coated with a mixture of two or three emulsions. One emulsion is sensitive to blue light and the other to green. By exposing the paper first to blue light and then to green any paper grade from 0 to 5 is theoretically possible. At one time this technique was very popular.

If you have a subtractive color head the cyan filter only subtracts red light which the paper is not sensitive to, so cyan not needed. Use yellow filtration to subtract blue light leaving more green in the light = lower contrast,use magenta filters to subtract green light, leaving more blue light in the mix = higher contrast. In either case you do not need the cyan filter.

cowanw · Feb 17, 2017

Gerald C Koch said:
Look at the color wheel.

Cyan + Yellow = Green
Cyan + Magenta = Blue

You therefor have the two colors that the VC paper is sensitive to.

I believe you may be confusing an additive system with a subtractive system.

RPC · Feb 17, 2017

Perhaps what he is thinking is that if you turn the cyan and yellow all the way up you will have green, and then make an exposure, and then turn the yellow down and the magenta all the way up (cyan still up) you will have blue, then make a second exposure. That could work, but as I said earlier would be cumbersome and unnecessary.

Gerald C Koch · Feb 17, 2017

Some might find it cumbersome but it IS another use for the cyan filtration. Perhaps I shouldn't have mentioned it as people are making too much of it.

bvy · Feb 17, 2017

Is this not just split grade printing using filtrations equivalent to the graded physical filters? I use 150M+0Y for grade 4.5, and 0M+162Y for grade 00, per Ilford's docs.

BMbikerider · Feb 17, 2017

Like a number of others have said, thre should be no need to use the Cyan filter. All the colours can be manipulated using the magenta or yellow or a combination of both. If as someone said they made a print needing 40M and 5 cyan. The same effect could have been obtained by dialing out the cyan filtration, then experimenting with the red and yellow filters in varying proportions. I would start by adding another 10m and 10Y (That is assuming you are using an enlarger which is calibrated in Kodak units. Durst enlargers are different.

I always make what is nominally called a 'Ring Around'. A series of colour prints with one that is perfect in the centre and a series of others with varying colour shifts. So you have a quick guide as to what filtration you need to get another print accurate. It is a lengthy job to do but is well worth it.

So for example you have your perfect print which needed 50M and 50M make another by subtracting 5 yellow, then another with 20 units less and a third with 40Y removed. Repeat this for the other 5 colours red, blue, cyan, green and magenta. Make sure you assess the 'perfect' print in daylight when you are setting a base line. Any artificial light is not good enough.

wiltw · Feb 17, 2017

BMbikerider said:
Like a number of others have said, thre should be no need to use the Cyan filter. All the colours can be manipulated using the magenta or yellow or a combination of both.

that works OK some times, but if your pack needs 0Y 35M 10C, how do you get another -10Y so you don't need the 10C

bvy · Feb 17, 2017

BMbikerider said:
Like a number of others have said, thre should be no need to use the Cyan filter. All the colours can be manipulated using the magenta or yellow or a combination of both. If as someone said they made a print needing 40M and 5 cyan. The same effect could have been obtained by dialing out the cyan filtration, then experimenting with the red and yellow filters in varying proportions.

If you're at 0C+50M+0Y and still have a blue or cyan cast, how do you get rid of it without using cyan?

cowanw · Feb 17, 2017

We are confusing Colour and Black and White printing.

Cyan setting on color enlarger?

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