U of S | Mailing List Archive | alt-photo-process-l | spots and dots and UVBL solarplates

spots and dots and UVBL solarplates

Good morning all,
I've been thinking about this dotty discussion...it's interesting that I have never noticed a spot discussion on the list until after MONTHS of discussing it re: solarplate, and then FINALLY it comes out that other processes have this issue. Several of you, e.g. Sandy King, have it. I wish that it was mentioned way back when, Sandy and others, that you had this issue with other processes, too, because that would have helped narrow down the culprit much more quickly (and saved me big bucks).

I have never seen this with gum so assumed it was a characteristic of photopolymer only until others came forward. I also assumed that it was a factor of UVBL in combination with photopolymer and then come to find out the spotty issue continues to plague those with expensive point source lights. So, if the spots are truly just Newton Rings and a factor of the top side of the transparency in contact with the glass also, that seems much more manageable in the long run--see what the list can do if we take the time to share? Maybe we should spray the top side of Pictorico with Krylon?

One last thing about spots--if these plates are used for computer chips (am I not mistaken?) then the computer industry has GOT to have solved this problem...

But my real question is this: why has UVBL been considered a bad source for photopolymer, that point source is better if, in fact, the spot issue still is a factor with point source? I cannot see anything wanting in my UVBL images, except the spot issue. I can see that when the aquatint exposure is too great, the image becomes mushy (Susan, like your step wedge image at the bottom of your blog), but if the aquatint screen and the positive are in a 2:1 to let's say 1:1 the images are sharp and tonal. Until I get that ol' Amergraph I won't be able to do a side by side to see the dif, but what is it I might expect when switching to point source that will "wow" me?