Photopolymer help


Im sure youve seen it all before so heres another … ok so I have the kf152 photopolymer plate from Lyme bay press uk. I using a cheap-ish exposure unit (im just starting out, iknow iknow lol) this orange one:

I exposed for 500 on the timer which is a little over 8 minutes, does anyone else here use this unit? The finer lines are washing out and the bolder areas have no shoulder, should I go back to using this unit for longer exposure or give it up as a bad un’?

I have had over extended washout times, Ive just bought but not yet recieved the boxcar brush. I hope this might help? in your opinion is it more likely exposure or washout or a bit of both?
many thanks in advance, liz

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You need to increase the exposure. You don’t have the best exposure unit on the planet.


Thanks Gerald will give it a try. Yeh need to save pennies for a new unit prob, its just difficult when you’re trying to get everything together at the same time on a limited budget. I’ll get there W.I.P.


I had a bulb not working in mine I had the same problem - which as Liz said, need more exposure.

Is there a vacuum bed?

First step should always be to do test exposures with grayscales to find the manufatcurer’s recommended step (there are variations on Stouffer scale, and other scales as well). then adjust for image type (more for isolated line and dot detail or fussy serifs, less for solids and reverses). This is the only way to discover what exposure is “normal” for your specific lamps—which may be fresh and bright, or or old depleted, or randomly dead.
Every different combination of plate and exposure unit must be tested. There is no one correct exposure for everything.

Macdermid has a number of technical resources downloadable eg how to tes exposures too.

Thank you Paul, Parallel_imp and jonathanjeclipse. I had a chat with the guy at lyme bay press and he has helped a lot also. I do have a stouffer strip I am embarassed to say I didnt try it. Thanks for the help its appreciated!