unsharp maskinggreenspun.com : LUSENET : Large format photography : One Thread
There have been a few questions about unsharp masking in this forum. For what it's worth, I have been trying masking for a while now and I really like the effects. The internal or local contrast is enhanced while not killing the overall contrast. I expose film at high elevations like Bodie Ghost Town at 9000 ft. and the eastern sierra, and the contrast is sometimes horrendous. Contrast and unsharp masking brings the negative within range of the paper. It works on the highlights without flattening out all the overall contrast. I use T-Max 100 or Plus X for my masks. I use it on 4x5 and up. You will need some frosted drafting acetate from a drafting supply or art store. I use .005" and .007" acetate. You will also need a heavy piece of glass like you use when doing contact prints. Raise the enlarger all the way up and stop down your lense all the way. You will want a negative that is very diffuse. You want a negative mask that shows very diffuse density in the highlight areas, even less density in the mid tones and no density at all in the shadows. Only zones 6 and up do you want any density. I stack both pieces of film emulsion side up with the drafting film in between. I have cut the drafting film to the exact size of the film I'm using. I even the film and acetate edges together and then lay them down as carefully as possible on my baseboard. When I lay the film stack down I run my finger over the top of the film stack lightly to push out any air trapped between the stack. I then lay the glass down carefully so that I don't move the film stack. It is very, VERY important to make sure that the film stack is not moved. If it is moved at all it makes realigning the mask and negative that much harder later on. Exposure on my setup is about 3 seconds at f45. I use HC110 at a dilution of 1:20 stock to water at 70*f. After drying I realign the two negatives with each other using my light box and a magnifying glass, taping the edges together. The edges of the film base+fog areas is where I try to make the match. There after I always print the sandwich together. The results are well worth the effort. It sounds complicated but is very easy. Do one and you will use it often. Condit Manufacturing makes a registration system that is not too expensive. Try it and Let me know of any success or failures. E-mail me and I might be able to clear any questions up. If you can, take a workshop from Howard Bond. His workshops are inexpensive and a lot of fun.
-- james (firstname.lastname@example.org), November 01, 1998
I have the Condit system and it does work very well. However, it was fairly expensive. As I recall, the punch and frame were in the $400 range. The punch I ordered can be used with anything from 35mm to 5x7. The punch for 4x5 alone was a little less but not much. Having now used it a good bit I realize that aligning the mask with the negative isn't all that difficult a task and there are other, far less expensive, ways of doing it. So I think if I had it to do over again I probably wouldn't spend the money for the Condit system, excellent as it is.
-- Brian Ellis (email@example.com), November 02, 1998.