B&W printing using color head

amellice · Mar 26, 2015

So I spent last night trying to print a kind of hard negative, exposure time was short at f/8 for any practical dodging and burning. I thought that I could add Cyan to increase the exposure time so I dialed in 100 to get extra 10 seconds, did another test print and nothing happened! I dialed in another 100 to get total 20 seconds extra and also nothing happened. Still exposure time needed to short at f/8. Then it hit me that I was idiot! Adding Cyan alone won't do anything as B&W paper isn't sensitive to Red, what I need to do is to add Cyan along with Magenta and Yellow with the same amount. The chosen grade was 4 so Magenta and Yellow were above 0, what I need to do is to add to them whatever I'm dialing into the Cyan. So if I added 50 Cyan then I need to dial in extra 50 for both Magenta and Yellow to get ND extra 5 seconds. Is this correct?

ParkerSmithPhoto · Mar 26, 2015

I spent/wasted a lot of time trying to get a color head calibrated for VC papers, and was so much happier when I went back to the Ilford filters. Finally I was seeing the contrast that I needed. I know some people love the color heads for VC printing but it was a big fail for me. I'd rather spend my time making more photos.

snapguy · Mar 26, 2015

feed

I'm feeding my dog some fresh cat food and he ain't happy. What is wrong with my dog?

Luis-F-S · Mar 26, 2015

Adding 50 of all three ads 1 2/3 stops. Any reason U don't stop the lens to f11?

amellice · Mar 26, 2015

Luis-F-S said:
Adding 50 of all three ads 1 2/3 stops. Any reason U don't stop the lens to f11?

Exposure time before adding to the 3 of them was too short on f/8 (5~7 seconds) so adding ND and keep the same aperture would increase exposure time for practical use.

wildbill · Mar 26, 2015

I've been using colorheads since I started and I split grade print everything. I never touch yellow and only use 170 of cyan or 170 of magenta, for grades 0 and 5. If i need ND when printing a thin neg, I use an nd filter.

ic-racer · Mar 26, 2015

Any time Magenta and Yellow are used in combination you are producing neutral density for othochromatic emulsions. Production of neutral density is also the only reason to combine both Magenta and Yellow when exposing multigrade emulsions.

MartinP · Mar 26, 2015

Very strange. It seems like some people might want to re-read the Ilford Contrast Control pdf document.

(I can't post a link at the moment but will do so when I get home.)

Edit: It turns out that I can attach a local copy of the file. To find out about the colour of light involved in Variable-Contrast paper from the major manufacturer, read the attachment.

MrBrowning · Mar 26, 2015

MartinP said:
Very strange. It seems like some people might want to re-read the Ilford Contrast Control pdf document.

(I can't post a link at the moment but will do so when I get home.)

Here's a link to it.

http://www.ilfordphoto.com/Webfiles/2010628932591755.pdf

MartinP · Mar 26, 2015

MrBrowning said:
Here's a link to it.

http://www.ilfordphoto.com/Webfiles/2010628932591755.pdf

Thank you. (I also found that I had a copy of the pdf which was postable as an attachment - they appear to be the same version).

I was a little surprised to read of an earlier poster achieving a full range of contrast by using cyan filtration, hence me wanting some factual information listed in the thread.

Outside of colour reversal, has anyone ever used cyan filtration in a routine printing method of anything at all? If so, what? I'm curious.

The answer to the OP problem would be a smaller aperture (which may affect the qualities of the lens), a smaller bulb (which is inconvenient to change, even if a less powerful bulb exists), a neutral density filter placed under the lens (as most colour enlargers won't have a filter drawer) or a colour head with neutral-density filtration built in. I had thought that the last option was standard, but perhaps not.

ic-racer · Mar 26, 2015

MartinP said:
Outside of colour reversal, has anyone ever used cyan filtration....

I have used the cyan filter on my kids enlarger to show them how I can make the enlarger project different pretty colors, in an effort to teach them a little about light.

RPC · Mar 26, 2015

MartinP said:
Outside of colour reversal, has anyone ever used cyan filtration in a routine printing method of anything at all? If so, what? I'm curious.

Not necessarily routinely, but it can be used to create neutral density when color negative printing, with equally added amounts of yellow and magenta.

amellice · Mar 26, 2015

I'd like to understand how Cyan can be used to control the contrast as mentioned by wildbill. And yes I think you can use Cyan to add ND, so let's say that you decided to print on grade #2 which for example has M0 and Y0 but you found out that exposure time is to short for practical dodge/burn, you can add 100 Cyan and 100 to the M and Y value resulting in filters value C100, M100, Y100. In essential this is ND because you are blocking white light but you are still printing on grade #2.

@ic-racer I think adding Magenta and Yellow together doesn't count as ND, sure you increase exposure time because the light has been decreased by the added filters but it's not ND. ND would be changing the exposure time without changing the contrast. Changing Magenta and Yellow alone doesn't do that.

In the Ilford Contrast Control document that has been shared here, Ilford mentioned 2 ways to control contrast either by changing only 1 channel at a time or changing 2 channels, they are saying (claiming) that controlling contrast using 2 channel doesn't required to re-evaluate exposure time when changing grades, but for 1 channels it's required to re-evaluate exposure time.

spijker · Mar 26, 2015

amellice said:
... they are saying (claiming) that controlling contrast using 1 channel doesn't required to re-evaluate exposure time when changing grades, but for 2 channels it's required to re-evaluate exposure time.

Ilford actually states the opposite:

Single colour filter settings
However, as the yellow and magenta filters have not been arranged to equalise exposures, new exposure times will have to be recalculated when the contrast is changed.

Dual colour filter settings
Dual filtration values usually need longer exposure times than single filtration values, but should need less adjustment to exposure times when changing contrast.

amellice · Mar 26, 2015

spijker said:
Ilford actually states the opposite:

Single colour filter settings
However, as the yellow and magenta filters have not been arranged to equalise exposures, new exposure times will have to be recalculated when the contrast is changed.

Dual colour filter settings
Dual filtration values usually need longer exposure times than single filtration values, but should need less adjustment to exposure times when changing contrast.

Yes sorry my bad I flipped the rule, thanks for the correction, will edit my post

cliveh · Mar 26, 2015

amellice said:
I'd like to understand how Cyan can be used to control the contrast as mentioned by wildbill. And yes I think you can use Cyan to add ND, so let's say that you decided to print on grade #2 which for example has M0 and Y0 but you found out that exposure time is to short for practical dodge/burn, you can add 100 Cyan and 100 to the M and Y value resulting in filters value C100, M100, Y100. In essential this is ND because you are blocking white light but you are still printing on grade #2.

@ic-racer I think adding Magenta and Yellow together doesn't count as ND, sure you increase exposure time because the light has been decreased by the added filters but it's not ND. ND would be changing the exposure time without changing the contrast. Changing Magenta and Yellow alone doesn't do that.

In the Ilford Contrast Control document that has been shared here, Ilford mentioned 2 ways to control contrast either by changing only 1 channel at a time or changing 2 channels, they are saying (claiming) that controlling contrast using 1 channel doesn't required to re-evaluate exposure time when changing grades, but for 2 channels it's required to re-evaluate exposure time.

ic-racer is correct, as the reason for adding Magenta and yellow together at set values is (in theory) to change contrast without changing exposure time. However, it seldom works in practice.

RPC · Mar 26, 2015

I don't see how using the cyan filter does anything with b&w VC papers. Theoretically, a cyan filter works by passing completely blue and green, and subtracting red. As the OP stated, b&w paper is not sensitive to red so if you add cyan there should be no change, not counting any inefficiency of the filter. There would always be the same amount of blue and green hitting the paper despite the cyan setting. On the other hand, adding both yellow and magenta in equal amounts should result in neutral density since blue and green would be subtracted equally. It would not be necessary to use cyan.

pentaxuser · Mar 26, 2015

None of my business really but I am still curious why the OP doesn't simply change the aperture to f11 which gives double exposure. I use f11 quite often and have never noticed any deterioration in the print from f8.

There might be some deterioration at f16 but whether you'd see it might depend on how big the print was.

Nothing wrong with trying to understand how to dial in ND in a colour head although I confess to some confusion as a result of what appear to be conflicting posts but as a first step I'd move to f11.

pentaxuser

amellice · Mar 26, 2015

pentaxuser said:
None of my business really but I am still curious why the OP doesn't simply change the aperture to f11 which gives double exposure. I use f11 quite often and have never noticed any deterioration in the print from f8.

There might be some deterioration at f16 but whether you'd see it might depend on how big the print was.

Nothing wrong with trying to understand how to dial in ND in a colour head although I confess to some confusion as a result of what appear to be conflicting posts but as a first step I'd move to f11.

pentaxuser

moving to f/11 is a correct solution to the situation. I've Nikkor 50mm f/2.8 and I like to print on f/8. to be honest I don't know why I didn't simply close the aperture one stop. about 90% of the time I print on f/8 with this lens

cliveh · Mar 26, 2015

amellice said:
moving to f/11 is a correct solution to the situation. I've Nikkor 50mm f/2.8 and I like to print on f/8. to be honest I don't know why I didn't simply close the aperture one stop. about 90% of the time I print on f/8 with this lens

Do you need to dodge and burn?

ic-racer · Mar 26, 2015

cliveh said:
iMagenta and yellow together at set values is (in theory) to change contrast without changing exposure time. However, it seldom works in practice.

A properly constructed table of values will, by definition, keep a specified gray value constant through the entire spectrum of contrast settings. (there was a url link here which no longer exists) Otherwise, yes one is better off just using single color filtration when printing.

RalphLambrecht · Mar 26, 2015

ParkerSmithPhoto said:
I spent/wasted a lot of time trying to get a color head calibrated for VC papers, and was so much happier when I went back to the Ilford filters. Finally I was seeing the contrast that I needed. I know some people love the color heads for VC printing but it was a big fail for me. I'd rather spend my time making more photos.

I always printed with a calibrated Durst color head and never went back to the clumsy and coarsli stepped filter packs but the OP's question has my neurons in a iwist.

henpe · Mar 27, 2015

Slightly off topic; since I only print bw I decided to replace my dichroic cyan filtet with a small aluminum plate full with drilled holes (I made this plate myself in less than 30min). When I now dial in cyan, the plate goes up in the light-path physically blocking the light and hence acting as a ND. An easy mod if yor enlarger does not have a ND per default.

RobC · Mar 27, 2015

I tested cyan filter as ND tool many years ago. My conclusion was that it didn't work very well. Cyan does have an effect on contrast. Its a filter and only passes cyan light. However the cutoff of the emulsion layers colour sensitivity isn't so sharp that cyan won't have any effect and green or blue light will be affected in unknow amounts without some very careful testing. Result is I don't use cyan for ND.

Much simpler is to buy a sheet of Lee ND lighting filter which is very cheap and can be cut to size to fit above, below or in your light mixing box. It comes in 0.15, 0.3 and higher densities. The 0.15 is best. You can add as many layers as you need to get the print times you want.

http://www.leefilters.com/lighting/colour-details.html#298&filter=tf

filter product number 298

Note: its a lighting filter and heat resistant. AND its not optical quality (hence very cheap) so don't use it below the negative.

RalphLambrecht · Mar 27, 2015

RPC said:
I don't see how using the cyan filter does anything with b&w VC papers. Theoretically, a cyan filter works by passing completely blue and green, and subtracting red. As the OP stated, b&w paper is not sensitive to red so if you add cyan there should be no change, not counting any inefficiency of the filter. There would always be the same amount of blue and green hitting the paper despite the cyan setting. On the other hand, adding both yellow and magenta in equal amounts should result in neutral density since blue and green would be subtracted equally. It would not be necessary to use cyan.

+1

B&W printing using color head

Attachments

Privacy & Transparency

Privacy & Transparency