dichroic head and variable contrast printing
I just purchased an Omega D5 Dichroic and would like to know the various color combinations to mimic the ilford variable contrast filters. Can someone help me out?
You mention Ilford filters...are you using Ilford paper too?
The following link is to Ilford's website page with all their papers listed. Click on the paper you use, then click on "fact sheet" where you'll find information on dichroic filtration.
Note to self: Turn your negatives into positives.
there should also be a spec sheet in each pack of paper that will recommend starting numbers. feel free to tweak for you specific environment.
Filter settings are usually included with packs of paper - certainly Ilford always comes with a data sheet which lists filter settings that match their Multigrade filters fairly closely.
Omega colour heads use Kodak filtration units so for example grade 2 would be 41Y+32M if you choose the dual filtration method (which keeps exposure times reasonably consistent grade to grade).
I don't know if it's just my eyes, but I noticed certain tonal differences between the Ilford filters and the recommended equivalent filtrations. I used M+Y filtration, not just M or Y, and though I achieved the same overall contrast, the "look" just wasn't the same.
I wonder if it's simply a question of fine-tuning color balance. The way I understand it, VC filters are a mixture of Y and M, so if you have proper M amount on your dichro head, but you are deviating of a few CC of Y, you will not get the same results.
Is there anybody with a colour analyser and VC filters who could confirm that to me? I ended up sticking to the Ilford filters just because I hate fiddling forever to get the contrast right.
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, Vol. 1 (8 Jan. 1819): 8-29. p. 11
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If you want to calibrate it yourself, try this Paul Butzi guide. Personally, I use split grade printing and absolutely LOVE IT. I can't imagine using VC paper any other way. Best. Shawn
Thanks for the leads guys. I appreciate it the help.
Sorry to hijack the thread a bit, but the OP's question seems to have been answered, and mine didn't seem worth starting a new thread over...
I've got a Fujimoto enlarger and one of the dichroic filters (magenta) has had part of the coating wiped off... here's a quick snap...
... as you can see the coating has been wiped off, but only on a couple of areas in the centre... the majority of the coating is still there. I won't be doing colour prints but I do want to make prints with b&w VC paper... any idea if that amount of damage to the coating is likely to cause major problems? Thanks in advance.
Remember that the filters are density balanced to achieve the same transmission, while the Dichro head using just Yellow and Magenta is not. That could be some of the difference in how it appears. You can dial in some blue to maintain constant speed, but I don't do it, and can't say how much.
Originally Posted by mhv
I also have the Omega D5 with Chromega D Dichroic head and have wondered about Ilford MG paper and using the dials on the head vs. a filter set.
Would the round ones fit OK in the Chromega head? The drawer seems a bit wide (and maybe short) for them. I believe they come in bigger squares that would fit (but I have the round ones, and no under-lens filter holder).
In any event I'm curious about the "density-balanced" aspect of the filters. Ilford mentions this negates the need to make a calculation (http://www.ilfordphoto.com/applications/page.asp?n=117). I'm not sure what this means, as there is a chart which seems to indicate Omega heads fall under the Kodak umbrella of filtration; this chart also indicates the dial setting to achieve the various contrast levels. How is using the filter set simpler or beneficial?
With the filters, apparently half use one exposure; the other half, double that exposure.
"Most important of all, though, is the fact that the filtration in your colour head is not density-balanced. Each time you change filtration, you will need to carry out a calculation to determine the new exposure time. MULTIGRADE filters are not expensive, and using them will save you much time and trouble."
(I think this might be the answer to my question - with filters once exposure is know, it's either 1x or 2x the exposure depending on the filter, with the head exposure is different with each setting?).
Thanks for any insights into filtering with MG paper. I'm using MGFB Warmtone. Have any of you decided filtering was not necessary to achieve the look you wanted on MG paper? I'm not sure, but I think some prints I made initially w/o adding magenta, also had fine contrast and sharpness.
Last edited by gothambill; 12-03-2008 at 05:23 PM. Click to view previous post history.