[pure-silver] Re: B&W Positive from B&W Negative.
----- Original Message ----- From: "Speedy ." <speedgraphic@xxxxxxxxxxx> 
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Tuesday, June 26, 2007 4:27 PM
Subject: [pure-silver] Re: B&W Positive from B&W Negative.



Richard,
Apparently this guy has negatives that he wants to make positive images of for projection.
I know he could scan the negs and create digital images, but he really wants to stick with a silver process. Essentially he is trying to take a Negative produced at some time in the past and from that negative create a postitive image that he can project.
At the moment he is thinking of attempting to use a slide duplicator to copy the negative on to negative film and figuring that a negative of a negative should produce a positive image...
I will look into the fine grain Release Positive film you mention. 

Thanks!
Speedy
FGRP would be ideal, if you can find it in reasonable quantities. Kodak used to put it up in 100 foot spools but I think now the shortest is 1000 feet. However, there are specialist dealers in what are called short ends. These are remenants of motion picture films, typically less than 1000 feet. There is a data sheet for FGRP on the Kodak web site and I probably have one in my archives if you can't find it there. The film is about as fast as Kodabromide was, about the same speed as fast VC paper with no filter. The contrast can be varied over a moderate range by choice of developer. The developers recommended are all pretty active, D-19 and Dektol for example, because a projection transparency must be of rather high contrast and must have very dense blacks. The film is extremely fine grain. One can make 35mm slides on it from large negatives by reduction. If it turns out that FGRP is not available my next choice would be T-Max 100. Its fine grained enough but the speed will make it more difficult to work with. Again, the transparencies must have high contrast and dense blacks. T-Max is capable of both but has the gray pigment in the support which cuts down projected brightness by about a stop. Not a big deal if you don't mix the slides with others on clear film base. FGRP is blue sensitive and can be worked with under a red safelight but T-Max is, of course, panchromatic, so must be processed in the dark. Strips can be processed in a tank so this is not too great a problem. The enlarger light must be attenuated quite a bit and likely some form of shutter should be used for exposure control. Development shold be in a rather high contrast developer, perpahs D-19 although Dektol might be OK if its not too high in contrast. Some experimenting will be necessary. T-Max 100 reportedly works well for reversal slides so it should work OK for diapositives (bet you haven't heard that word for a while). I have not much experience with either Ilford Delta 100 or Fuji Acros but they are similar to T-Max and I suspect would also work well. 

---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx




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