Thought I'd share a solution that solved a major printing problem for me, that others may benefit from...

I've had many problems with focus shift of 35mm TMax 100 and 400 (TMX and TMY) negatives with my recently purchased Omega C760 dichroic enlarger. When I replaced my condenser enlarger with the C760, I expected that the diffusion head of the C760 would eliminate this problem, that occurred with most films in my old enlarger, as the result of the negative heating and "popping" (more like "creeping" if you watch it happen through a grain focuser) in the glassless carrier.

Although the C760 fixed the problem for most films I use, TMX and TMY negatives continued to shift as they heated in the C760. I can only attribute this to these films using a thinner and less stable film base that makes them more prone to heat pop. After trying the alternative of leaving the enlarger "on" to keep the neg at its "popped" position, I gave up as the result of the inconvenience of this process when dodging and burning, and inconsistent print sharpness. I looked at glass negative carriers to solve the problem only to find that the carrier for the C760 is a 6x7 fixed format, with top glass only, which I didn't consider adequate for keeping a 35mm negative flat.

Since then I've lucked into a rediculously simple, effective and inexpensive solution that consistently gives me sharp prints with no heat pop. The solution - buy a $12 box of 20 GEPE anti-newton glass slide mounts for 4cm x 4cm "superslides". Being very careful not to get the glass dirty, or to cut yourself on the glass or the mounting frame, take a half mount, cut it's thin inner mounting frame, and remove the glass. Open the negative carrier and position the negative on the carrier's lower plate. Carefully trim the glass to fit on top of the negative without fouling the carrier's negative alignment pins, and gently place the glass, with the anti-newton side on top of the negative, and close the top of the carrer. Voila - a flat, stable negative.

Other benefits - this adapted glassless carrier keeps 35mm negs more accurately placed than would a larger format one-sided glass carrier, and the slight amount of slack in the hinge of the negative carrier allows the thin anti-newton glass to be placed on top of the negative without distorting the carrier or causing enlarger alignment problems. There's also no need to worry about scratching the glass of a specialized glass carrier, as you've got 39 backup pieces of glass that came with the first one.

-- Dave Williams (davidw@ca.ibm.com), January 24, 2001

Answers

...I tried this and got a weird, faint texture due to the AN glass on my prints (very, very subtle, but there). This was with a condensor head, though. Do you still have this "texturing" with your dichro head?

-- MR (reynard75@hotmail.com), January 28, 2001.