U of S | Mailing List Archive | alt-photo-process-l | Re: Yellow tents and UV (was: outdoor gum demo)

Re: Yellow tents and UV (was: outdoor gum demo)

Oops, my mistake, sorry. Can't say much about that otherwise, since it's (obviously) not a process I've ever done, and I haven't done a great lot of gum printing in the sun either, but when I have, generally when doing a lot of tests that I wanted to get through in a hurry, it was just faster to do it in the sun since an exposure was less than a minute, and not longer at different times of the day or year, always pretty much the same.

At any rate, certainly different processes rely on different wavelengths and respond to radiation differently.

I'm not insisting that there should never be any variation in sun exposure for any process; all I'm arguing is that since UVA doesn't vary directly with UVB, it doesn't make sense to use UVB as a surrogate to determine UVA levels. That's all I'm saying; that's my whole point.

On Apr 22, 2009, at 1:02 PM, Paul Viapiano wrote:

Centennial POP (Chicago Albumen Works) was (sniff!) sensitive to blue and UV only...(from their website).



----- 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.