Re: Yellow tents and UV (was: outdoor gum demo)
Can't pass w/o mentioning this also (from the same page, a little more below the previous quotation): "...Printing times using daylight will be varied, with the exact time depending on the density of the negative being printed and the quality of the light, ie., the sky conditions, the time of day, and the time of year." Curious...... 22 Nisan 2009, Çarşamba, 11:14 pm tarihinde, Loris Medici yazmış: > A little below says: > > "EXPOSURE > The printing speed of this paper requires exposures be made by contact > under illumination by a strong ultraviolet light source, such as direct > sunlight, open sky, mercury vapor lamp, or black light printer. > Exposure times with such sources will be measured in minutes. Increased > contrast, of more than one printing grade, may be achieved by exposing > for extremely long durations (24 hours or more) under fluorescent > illumination. > ..." > > So any blue sensitivity is probably not enough to form an image, maybe it > was mentioned because it can slightly fog the paper - who knows? "24h > fluorescent light exposure?" -> Even ordinary enlarging paper will > considerably change tone at that level of exposure to visible light. > > Regards, > Loris. > > > 22 Nisan 2009, Çarşamba, 11:02 pm tarihinde, Paul Viapiano yazmış: >> Centennial POP (Chicago Albumen Works) was (sniff!) sensitive to blue >> and >> UV >> only...(from their website). >> >> http://www.albumenworks.com/directions.html >> >> >> Paul >> >> >> >> >> ----- Original Message ----- >> From: "Katharine Thayer" <kthayer@pacifier.com> >> To: <alt-photo-process-l@usask.ca> >> Sent: Wednesday, April 22, 2009 11:57 AM >> Subject: Re: Yellow tents and UV (was: outdoor gum demo) >> >> >>> >>> 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. >>> >>> kt >>> >>> >>> >> >> >> > > > >
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