Hello everyone !

I have been given ( :-> ) a color dichroic enlarger, and I also would like to use it as a B&W enlarger. The paper manufacturers give correspondance sheets in order to use a dichroic enlarger with their papers. For instance, Agfa tells to set 80Y for grade 0, 30Y for grade 1, nothing for grade 2, and so on ...

My question is : What about the time ? When you add filtration, less light goes through the filters, so may be you should compensate this light loss with a longer time ???? Agfa does not say anything about it, but ilford does ... I am a little bit confused. Of course I can try, test, and calculate the time on my own, but a little help would not hurt !!!

Thank you

-- Anonymous, April 11, 1997

Answers

Dichroic

Start at what they reccomend for a #2, do a time test, get a good print density. From there it's like this: More magenta, more contrast, exposure has to be lengthened for same print density. Less magenta, less contrast, time must be shortened. More yellow, less contrast, doesn't affect exposure time much. Less yellow, more contrast, doesn't affect time much. No Cyan ever. Try playing with the suggested starting points, they sound good. You get used to it, after awhile you know automatically...from 10m to 20m add 25% of exposure time, that kind of thing. It becomes a system that works by feel.

Hope that helps.

Mike

-- Anonymous, April 11, 1997

Yes, the more filter means less light. Adding yellow does not block the light like the cyan for the same filter number. (At least with the papers i have tested.) The best thing to do is test it yourself. Make prints from 0 grade to 5 and make sure the HIGHLIGHTS match in each print. I did this test for a school project and it cost me some money in paper but then I KNEW when I changed the paper grade what the effect would be.

-- Anonymous, April 28, 1997