U of S | Mailing List Archive | alt-photo-process-l | Re: solarplate wedgies

Re: solarplate wedgies

This weekend I had to print an edition on solarplate and I had chosen chine colle as part of this print's process. What a stupid mistake. My KM73 plates that were exposed for 49sec aquatint/41 seconds positive and post hardened extensively (I noticed that when the plate is hardened it goes from pale celery to pale aquamarine) the chine colle with its moisture dissolved the surface of the plate. I did this once and thought, well maybe the plate was just breaking down and Jon was right--you can't get a lot of pulls on one plate. So I went home, made two more plates, and brought them back. Same thing happened again. Needless to say, you can imagine how frustrated I was wrecking three plates!!! Even tho the back of the chine colle was dry, of course when run thru the press it squeezed through to the surface of the plate. I finally had to chine colle without moisture, in essence printing on top of the tissue paper in register with the back paper, and will post glue it. Any of you chine colle with KM73?

I did make about 35 prints this weekend, btw, and the plate held up fine, so if there is no moisture it is sturdy.

I also found out one more thing (where are you Susan, Jon, Keith? Spring break??). This leads back to what I said about wedgies and my surmise that you can use a number of different exposure times but the ratio is the most important. The plate that was exposed UVBL 49/41 which looked tonally really nice was much less sturdy than the plate I finally printed from which also looked tonally very nice--2min/45 seconds. In fact, that plate produced a sharper, darker print. I am thinking this and correct me if I am wrong:

The plate is .73mm thick--the longer the exposure, the thicker the "goo" on top stays, up to a certain point where the whole plate is overexposed and will print complete white. I think it is like gum printing! With gum, you can choose a shorter or a longer exposure time and the layer of gum arabic/pigment is thicker or thinner (vertically) but also a deeper color happens the thicker the layer because, naturally, there is more pigment suspended in a thicker layer vertically.

So, I am going to stick with my original theory that it is not the exposure time that is crucial but the ratio of aquatint to positive that is the most important. I can test this by doing a, let's say, quadrupling my 49/41 ratio for instance, and probably see if this assertion is correct. AND I wonder if that plate, thicker and harder, will be able to withstand chine colle better.

One other thing--I switched to PhotoWarehouse OHP and all inks on the 2400. I can manage to get one plate made from one neg before the neg breaks down (the ink comes off easily) and it will take all inks but not colored only--that smears. I had to, in "Ink Config" switch the pass time to 50 (5 seconds between each printer head pass) to make sure nothing smears also. the PWOHP is much thinner and more flexible than Pictorico. I did this because of the measle issue and several authors recommending that you switch substrates if measles occur. I powdered both the back and front of the OHP. I got one or two spots per plate in the very darks only and they did not print.

It is snowing here majorly--so beautiful, even though it IS April 2. But such is Montana...