Re: Yellow tents and UV (was: outdoor gum demo)
22 Nisan 2009, Çarşamba, 9:57 pm tarihinde, Katharine Thayer yazmış: > > On Apr 22, 2009, at 11:29 AM, Paul Viapiano wrote: > >> Now, of course, if there is cloud cover then all bets are off... >> >> I say this partly in jest because in my Darkroom 1 book (Lustrum >> Press), Linda Connor (whose exhibit I've just seen at the CCP in >> Tucson) said that sometimes she'd leave a POP print out on her back >> porch for 3 or 4 days! > > But that's a gelatin-silver chloride process exposed with visible > light, no? Apples and oranges, sorry. Of course if there's not > much visible light, it's going to take some time to make a print that > depends on visible light. But the amount of visible light isn't a > measure of UVA. I've exposed gum prints in the shade in 3 minutes, > and no, they weren't underexposed. If I'm not horribly mistaking, POP paper is mostly UV sensitive -> not much different than salted paper in that respect. Any print-out process would need high energy "light" e.g. UV, because there isn't any later developer action that chemically amplifies the reaction...