With 180 beginners, printing that many negatives would be a nightmare, unless you use laser transparencies and a fast laser printer. A student of mine had a $100 HP printer that spit out transparencies almost as fast as you push the send button. Another nice thing about the laser negative is that it is very exposure tolerant, that a little more or less exposure would not affect the details, just the darkness of the blue.|
Yes, the grays would be half-toned, but it would be very smooth and for beginners that's OK.
You might be able to get a good price on the transparency material also, even at surplus sites.
On Jan 29, 2008, at 4:29 PM, firstname.lastname@example.org
I tried again today. (I also teach high school photography, only I teach the wet kind) I was able to get OK prints, although the exposure time was extremely long. The transparency version was much quicker and snappier. Since I have 180 beginners, I don't think I'll spring for the transparencies.
On the plus side, the generic Sax 140 lb watercolor held a great blue without staining, even with a little acid in the wash.
From: henk thijs <email@example.com
Sent: Tue, 29 Jan 2008 9:29 am
Subject: Re: Cyanotype with high school students
Have you tried using paper negs?
Did you ???? I never had a good result with paper negs for cyanotype; for oil-printing and gum it was ok for me, but cyanotypes ....