Is it recommended to slightly (by what factor?) over develop BW film that will be enlarged using a diffusion enlarger? Any comments on this subject are appreciated! -Patricia

-- Patricia Arfsten (parfsten@cccd.edu), September 19, 2000

Answers

I don't. I can sort of see an advantage in slight overdevelopment, since it will increase the contrast that may be lost with diffusion, if you photograph scenes with low contrast. But in general, I think you can dial in whatever small differences you may encounter with no extra development, and there is also no problem if you every want to use another head--not that there is any real problem in the real world, just dial in the filtration, but 'in theory'...

Adams says develop a little more for diffusion heads, if I recall...

-- shawn (shawngibson_prophoto@yahoo.com), September 19, 2000.

If you're replacing a condenser head with a diffusion head, it's easy to make comparison test prints and see how much more magenta filtration you need for printing with the color head.

If you're taking a recommended development time and trying to adjust that without testing, forget it.

Generally speaking, negs that print well with no filtration on a condenser enlarger will need 25M-40M with a color head, but since condenser heads are _way_ different in what contrast each gives and color heads aren't calibrated to anything other than arbitrary steps, in reality all bets are off.

-- John Hicks (jbh@magicnet.net), September 19, 2000.

Most Multigrade papers come with a table showing paper grad versus colour filter, say Magenta 200 for grade 5. In general there seem to be two types of colour heads, with slightly different filtration. Using multigrade paper the contrast is controlled at the printing stage. If you use graded paper you might want to use about 20% more developing time as for condensor to increase contrast. (Which is reduced at the printing, as John said).

I think Ilford is selling books on their Multigrade papers (one for RC, one for fibre)have a look at them, or contact their website and look at the data sheets.

Agfa gives dev. times for a contrast of 0.65, which is closer to the diffusion enlarger. Fuji Neopan 1600 usually gives high contrast for diffusion.

Regards,

Wolfram

-- Wolfram Kollig (kollig@ipfdd.de), September 21, 2000.

WRT to filtration, who cares what is what Grade? More magenta is more contrast, more yellow is less contrast.

Since different papers differ as to grade versus actual contrast range, why even try to go there.

-- Terry Carraway (TCarraway@compuserve.com), September 22, 2000.