Use of color head for VC printing

[Csholl]

Hi,


I have a question regarding using a color head for black and white prints. My question: do you use both Yellow and Magneta filters at the same time, or if you want more contrast just use the yellow and less, instead, the Magneta? Also, can I get more contrast using Poly filters instead possibly?

[Oren Grad]

You can do it either way - see the discussion on page 3 of this Ilford publication on contrast control:

https://www.ilfordphoto.com/amfile/file/download/file/1824/product/1872/

Depending on the paper and the filter set you're using, a separate filter set may enable you to get a bit more contrast at the high end than your color head's built-in filters.

[xkaes]

Different colorheads have different upper ends to their filtration. Most "top-out" at 200 units on all three colors, but not all of them.

Some might say, you can fine-tune colorhead filtration, which is true, but I've never had a need for that.

Also, it's best to test for correct exposure with colorheads and filtration changes -- of course that's a good idea with poly filters too. I learned through simple testing that the manufacturers' suggestions are not 100% accurate.

[Axelwik]

The instructions for your color head will probably have a table detailing VC filter settings for B & W printing.

[xkaes]

For my Beseler Dichro 45S it shows only YELLOW or MAGENTA for the Ilford Multigrade filters, but it shows COMBINATIONS of YELLOW & MAGENTA for the Kodak Polycontrast filters.

[Drew Wiley]

Unless you want an amount of neutral density in order to slow down an exposure, there is no reason to use Y and M at the same time. Here the reason: A YMC subtractive colorhead uses "white light" (slightly yellowish due to the bulbs involved), and then filters out a certain amount of the complementary color, depending on the strength of the setting. Yellow on the dial with progressively filter out blue, and therefore decreases the paper contrast, while magenta on the dial will filter out a certain amount of the green light, and result in contrast
increase. But at anything less than the highest settings, a degree of all wavelengths will get through.

You really don't need to pay any attention to what does or does not correspond to Ilford or Kodak VC sheet filters. It's irrelevant. Besides, Kodak Polycontrast is as dead as a Dodo bird. All you need to know is that magenta light increases contrast, and does so to the degree you increase the M setting, while Y light does just the opposite, and decreases contrast to the extent you dial the Y setting higher.

If you can't get an extreme of contrast either direction, even at the highest setting either way, then you can use either a dark green 58 glass filter on the lens for even lower contrast, or a 47 blue filter for maximum high contrast. But that's kinda the nuclear option.

[Oren Grad]

The instructions for your color head will probably have a table detailing VC filter settings for B & W printing.

It's useful to look at the paper data sheets as required filtration for a given grade varies across papers, sometimes even within brands.

[Drew Wiley]

Why do "grades" even need to be factored into the equation? That's like ordering dentures for extinct dinosaurs. Just complicates a simple problem. VC papers provide a continuum, which varies not only brand to brand, but even developer to developer.

[Oren Grad]

Why do "grades" even need to be factored into the equation? That's like ordering dentures for extinct dinosaurs. Just complicates a simple problem. VC papers provide a continuum, which varies not only brand to brand, but even developer to developer.

They don't. Once you've worked with a given color head and a given paper/developer combination for a bit, you get a sense of what different M and Y settings do with your negatives, and that becomes your basis for choosing a filtration starting point for a negative. Grade specifications are different across manufacturers, papers and filter sets anyway, so it generally doesn't make sense to get hung up on what exact grade a color head setting is supposed to be achieving.

[Ironage]

If you are using Multigrade paper, there is a chart for each enlarger type that tells you what settings for each contrast grade. There is a chart that adds density to the filter pack so you don’t need to adjust exposure when you change grade. The instruction sheet is available on the ilford website that you can download. This will give a good starting point.


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[Csholl]

If you are using Multigrade paper, there is a chart for each enlarger type that tells you what settings for each contrast grade. There is a chart that adds density to the filter pack so you don’t need to adjust exposure when you change grade. The instruction sheet is available on the ilford website that you can download. This will give a good starting point.


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Ok..thx for the info. The link if I'm correct is...https://www.ilfordphoto.com/wp/wp-content/uploads/2017/03/Contrast-control-for-Ilford-Multigrade.pdf. As usual I will make my own test and then correlate each setting to the degree of contrast rendered. I have a few charts I can use and in books too. Not sure still if I can get more contrast with a poly contrast 5 filter but I'll test for this as well. thx again.

[Larry Gebhardt]

I don’t see the utility in using both for speed control since the speed is only ever matched at one tone and that isn’t at a point that works for my way of printing. So I either make new test strips when I change filtration, or I use split grade printing. Split grade has so many advantages that it’s my preference, but not if I have to spin dials on a color head.

[Drew Wiley]

Ironage - first of all, even dichroic filters in colorheads shift over time, due to either spalling off some of their coatings when old, or simply accumulating grime over the long haul. Second, those comparison charts only take into account a few common amateur colorheads. Third, dials and so forth aren't typically all that precisely calibrated unit to unit. Even if there are automated feedback loops monitoring the light for sake of repeat accuracy, those are dependent upon color sensors which themselves get dirty or otherwise affected over time. Simple test strips are so darn easy to do with VC paper that I simply don't understand the need for all the supplementary fuss.

[Torquemada]

Ironage - first of all, even dichroic filters in colorheads shift over time, due to either spalling off some of their coatings when old, or simply accumulating grime over the long haul. Second, those comparison charts only take into account a few common amateur colorheads. Third, dials and so forth aren't typically all that precisely calibrated unit to unit. Even if there are automated feedback loops monitoring the light for sake of repeat accuracy, those are dependent upon color sensors which themselves get dirty or otherwise affected over time. Simple test strips are so darn easy to do with VC paper that I simply don't understand the need for all the supplementary fuss.

The conventional wisdom behind the dichroic color head is that the filters are not supposed to wear out with usage, as the filter drawer based ilford set does.

However, the fuss is simple.. we want a reliable and affordable method to relegate a contrast grade to an image.. we dont want to have to do 30 or 40 test prints for every image we print.

Its not 1990 and we have to do 3 rolls of slide film so we can get the lighting just right for the final good slide image we take.

[wclark5179]

Info from Ilford for VC paper contrast control:

https://www.ilfordphoto.com/wp/wp-content/uploads/2017/03/Contrast-control-for-Ilford-Multigrade.pdf

[Tin Can]

I have a very old Color Head, no dichrolic filters

It has a strange lamp almost like the not invented LED

I replaced the OE Fan with computer Fan

and hold filters under the lens

in motion

workes great

and saved another CB7

[Drew Wiley]

Torquemada - Ironically, you're the one named after the torture chamber Inquisitor methodologist, not me. I typically need only one of two small test strips to tell me exactly what I need to do. It's fast and inexpensive. But Trying to pigeonhole modern VC paper response into old grade numbers that never were consistent brand to brand to begin with is a redundant waste of time and energy. And it won't get you a hole in one anyway.

No, it's not 1990 - most darkroom approaches have actually degraded from that era. Incidentally, I never bracketed even color chrome exposures. The invention of light meters solved that issue. And by 1990, color films were being very consistently coated batch to batch. And in 1990, I was mostly shooting 8X10 film, so trial duplicate exposures were out of the question - it had to be done right the first time, every time.

[Torquemada]

Torquemada - Ironically, you're the one named after the torture chamber Inquisitor methodologist, not me. I typically need only one of two small test strips to tell me exactly what I need to do. It's fast and inexpensive. But Trying to pigeonhole modern VC paper response into old grade numbers that never were consistent brand to brand to begin with is a redundant waste of time and energy. And it won't get you a hole in one anyway.

No, it's not 1990 - most darkroom approaches have actually degraded from that era. Incidentally, I never bracketed even color chrome exposures. The invention of light meters solved that issue. And by 1990, color films were being very consistently coated batch to batch. And in 1990, I was mostly shooting 8X10 film, so trial duplicate exposures were out of the question - it had to be done right the first time, every time.

That era is a bygone one, my only experience with film in the 1990s being a middle schooler who was allowed to get a really low cost film camera at a yard sale but never being allowed to purchase film. Because developing was to costly..

The modern age of RC VC paper does make the concept of "contrast grade" somewhat meaningless. With the companies putting so many developer accelerants into the emulsion in an attempt to make it more sensitive,, its not fun. Cant get Ilford to work with my dichroic head.. its either 1 "grade" to bright, or too dark.

[Larry Gebhardt]

That era is a bygone one, my only experience with film in the 1990s being a middle schooler who was allowed to get a really low cost film camera at a yard sale but never being allowed to purchase film. Because developing was to costly..

The modern age of RC VC paper does make the concept of "contrast grade" somewhat meaningless. With the companies putting so many developer accelerants into the emulsion in an attempt to make it more sensitive,, its not fun. Cant get Ilford to work with my dichroic head.. its either 1 "grade" to bright, or too dark.

Have you tried fresh Ilford below the lens contrast filters? Give them a try if you can. That should show you whether you are having an issue with the head or something else like the paper or your film development.

Another simple experiment is to print with no filters, which should give you a grade 2ish contrast. If your print contrast is off there adjust your development so it’s close. VC paper works best in my experience the closer the negative is to normal contrast.

In all of your tests ensure you a developing the paper long enough for the image to have stopped changing, also known as developing for long enough to reach maximum black.

[ic-racer]

The Ilford information in the supplied charts is good. I have made my own charts, but they are similar to the Ilford ones.

https://www.photrio.com/forum/threads/making-a-multigrade-calibration-table-for-color-head.42839/

[bob carnie]

The Ilford information in the supplied charts is good. I have made my own charts, but they are similar to the Ilford ones.

https://www.photrio.com/forum/threads/making-a-multigrade-calibration-table-for-color-head.42839/

Would you be able to post that chart here?

[ic-racer]

The two missing charts from the Phototrio thread:

241862
241863

[Drew Wiley]

Interesting to illustrate an obsolete paper, and in RC too boot, but hardly ideal.

[wclark5179]

Thought this information from Ilford might help:

https://www.ilfordphoto.com/wp/wp-content/uploads/2017/03/Contrast-control-for-Ilford-Multigrade.pdf

[angusparker]

My handy cheat sheet (in PDF) for VC paper and the CLS 500 head

242556

This is for a head with a Max magenta of 130.

[ic-racer]

Interesting to illustrate an obsolete paper, and in RC too boot, but hardly ideal.

Pardon me for sharing factual information rather than opinionated, off topic diatribe.

If the chart didn’t work for you then you might need to make your own assuming you have not already given up film photography, darkroom printing and other obsolete processes.