Placement of filters in enlargergreenspun.com : LUSENET : Large format photography : One Thread
Here's a question for folks familar with using multigrade filters. I print using an Omega D-2 and have a set of large square ilford multigrade filters that I use. I place them above the negative, actually right on top of the negative & carrier. I do this because my lens is too large to use the little filter carrier below the lens (the filter carrier partially blocks the illumination from the lens, even when it is stopped down to f22). Does anyone know of any pitfalls from using the filters by resting them on the negative before closing the enlarger head?
-- Mark DeMulder (email@example.com), December 19, 2001
If your Omega D-2 is a condenser head then the filters chould beplaced above the condensers inside the little flip-up cover. if you have an Omega filter frame this is where it suggested it be put.
Having the filters too close to the film increases the risk of imperfections, dust and marks on the filters show in the print due to the depth of field once you stop down. I have an aversion to placing anything in the lightpath between the negative and the paper (ie: above or below the lens.
Good luck ... Walter
-- Walter Glover (firstname.lastname@example.org), December 20, 2001.
you may get Newton-Rings when placing a sheet-filter directly onto the negative. I don't know the Omega D-2, but doesn't it have a seperate filter drawer?
-- Thilo Schmid (email@example.com), December 20, 2001.
You may have more problems when you use more than one filter to print a negative. Lot's of times you'll want to use different contrasts in parts of the image. This means changing filters under safelight. Your method makes it easier to hit the carrier disturbing the registration between the two exposures.
-- Chuck Pere (firstname.lastname@example.org), December 20, 2001.
Omega made lamphouses both with and without filter doors/slots. If you've got it, make an aluminum tray and use it. If not, then the above-the-neg method will work if you keep everything clean. You could also fabricate something to hold filters under the lens without getting in the beam path. I don't like anything above or below the lens, but Ctein tested this and concluded that there was no visible degradation, so you shouldn't worry too much.
-- Conrad Hoffman (email@example.com), December 20, 2001.
I have been using a Beseler 45MXT with a cold light head. The filter holder below the lens is quite small also, and I found that I was getting some "Newton rings" on some of my prints. I then started placing the filter directly atop the carrier, just as you are doing. The rings disappeared, but like a previous post said, the chance for dust marks are doubled because one must keep both negative and filter clean. Overall, the method works, but if I could figure a way to place the filter higher, I would do it.
Good luck with your printing!
-- James Webb (firstname.lastname@example.org), December 26, 2001.