B&W Printing on a Super Chromega Head
I just purchased an Omega D5XL with a Super Chromega lamphouse. Can anyone give me the Y and M filter factors I should use to print B&W?
Those will depend on the paper that you are using. Details of filter factors are normal give in the paper's printing instructions. If you are using graded paper then you should print using the white light setting.
Ilford has a page listing the settings for their papers... Try a search of the Ilford site!
Here is the settings for my Durst Dichroic color head, at least you can use these as a starter if you can't find the page on the Ilford site:
Dual colour filter settings
From the table below, read off the approximate filtration needed for each contrast step. Dual filtration values usually need longer exposure times than single filtration values, but should need less adjustment to exposure times when changing contrast.
MULTIGRADE Yellow Magenta
00 120Y 0M
0 88Y 6M
1/2 78Y 8M
1 64Y 12M
1-1/2 53Y 17M
2 45Y 24M
2-1/2 35Y 31M
3 24Y 42M
3-1/2 17Y 53M
4 10Y 69M
4-1/2 6Y 89M
5 0Y 130M
John (Alpha Flying Monkey) Moore
I use a chromega color head for B&W printing, and the Y and M factors vary by paper, but only mildly so. As a rule of thumb, I use a no-filter as a 2.5 or 3, and add yellow to lower contrast, or magenta to increase it.
How much filtration to add? 10 points will give you a very small change (good for fine tuning), 30 points will give you about half a grade, I think.
Full magenta will give you about a grade 4, 4.5, whereas full yellow might give you a lower than 00 grade.
Try it out and see, and I'm sure you'll be happy with it. It might take a printing session or two to get used to it, but its worth it.
BTW, I NEVER mix the colors... adding 10y and 20m increases the printing times a lot more than just 10m... at least on Forté paper. I can't explain why, but mixing yellow and magenta seems to make the enlarger light into a safe light... It's much better to simply add one filter at a time, and re-test for time once the contrast is dialed in.
just my 2c
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Ok, last post here, sorry (no intention to hijack, just stupid mistakes)...
Above I meant to say that, on my chromega head, 10y and 20m requires A LOT more time than simply 30m or 30 yellow... which throws the whole dual filtration thing out the window. Might be a unique problem, but at any rate using one filter at a time gives me great results.
keep in mind
30 magenta change = 1 full stop change
30 yellow change = almost no density change
Originally Posted by hblad120
These are for Ilford. Conventional wisdom is to use the "Kodak" numbers for Omega heads.
FWIW, I've got a Philips PCS130/PCS150 enlarger. The manual comes with tables with filtration values for Kodak and Ilford papers from 20 years ago. These tables are rather different from one another in the recommended values to get a given paper grade. A while ago I ran some tests with several papers (Kodak, Ilford, Agfa, Foma, and Oriental). I found that the Kodak, Agfa, and Oriental papers worked best with the Kodak table whereas the Ilford and Foma papers worked best with the Ilford table. (I was interested mainly in the "constant exposure" tables for producing constant exposure times when changing effective paper grade.) These results might not apply to other enlargers, though, particularly since the Philips has an unusual additive (red/green/blue light) color head, rather than the more common subtractive design (white light with cyan/magenta/yellow filters).
Also, if you're interested in really quantifying these things, the January/February 1997 issue of Photo Techniques magazine has an article on doing so. It describes how to determine the effective grade of your paper with a given filter set (or the filter set to use to obtain a specific effective paper grade). I haven't yet tried using this technique, though, so I don't know how well it works. It requires a step wedge negative and benefits from a reflection densitometer, neither of which I have at the moment.