RE: UV Box Heat Fogging?

Michael, 1" is pretty close indeed. In the other hand, I placed my tubes
3.5cm (~1 3/8") above the frame glass and the tubes are 5.5cm (~2 3/16")
apart each other (center to center, gap between tubes is 2cm) and I don't
experience uneven bands of exposure with this setup (I checked this by
exposing cyanotype - a quite contrasty emulsion - with a blank negative,
exposingfor ~1/3 the standard exposure time, then scanning the print and
boosting the contrast in Photoshop; there wasn't present any pattern
parallel to the tubes). Maybe the problem with the 21-step in the image
http://www.mondotrasho.ca/pages/alt-photo/stepwedges/VDBTern12minTest.jpg is
caused by these facts: your light source may be giving you uneven lighting
either because of 1) too close placement to the frame and/or tubes being too
far apart* or 2) variations in the tubes* - maybe both 1 and 2 together.

Regards,
Loris.

-----Original Message-----
From: Michael Koch-Schulte [mailto:mkochsch@shaw.ca]
Sent: 23 Kasım 2005 Çarşamba 01:16
To: alt-photo-process-l@sask.usask.ca
Subject: Re: UV Box Heat Fogging?

Seems to me I read about this in one of the issues of Post Factory. Maybe
I'll read it again. My light are only about an inch away from my paper maybe
this is too close. When I print longer maybe the problems become more
obvious.
I should have included this in the last post. This is how my "Red Green"
wedge printed out. I've exagerated the levels to show the oval in the orange
area in the upper left corner. That it's close to that magic pyro colour
should come as no surprise. Was there ever a "green" version of pyro?

http://www.mondotrasho.ca/pages/alt-photo/stepwedges/Red-Green-Printed.jpg

~m
Received on Wed Nov 23 03:48:48 2005