PreFlashing Harmon Direct Positive paper

[Dakotah Jackson]

In looking at controlling contrast with this paper - is it possible to give a very short exposure of the scene being photographed to act as the Pre-Flashing?

Or does it need a flat boost overall rather than one proportional to the scene or setup being photographed?

If it does need the overall - why not just a timed shutter exposure to push it to the threshold pre-flashing needed ?

[michael slade]

I didn't play with pre-flashing, but others have with good results.

[rjbuzzclick]

I've not used Harmon's Direct Positive paper, but I do preflash my paper negatives, and sometimes preflash paper before printing too. Preflashing paper reduces the white point to just above the point where it starts to turn grey. This reduces the contrast range of the paper. It needs to be done across the whole paper with even light to build up the exposure evenly. If you just take a quick "pre-exposure" of your scene, all you're doing is increasing your exposure time without adjusting the contrast range.

I preflash my paper by laying it on the floor of my darkroom (actually just a dark room) and holding a 4w night light bulb up at the ceiling. A 1 1/2 to 2 second burst of the light is about the right amount. It's easy to test, just do a test strip with an unexposed piece of paper and process normally. The correct amount of preflash is just less than the amount of time for the paper to just start to turn grey.