More gum notes: cold water shrink
Diana wrote:> I went back and found in your PFJ #6 (May 2001), a lot of really good information you provided about gum "rules" and also about one-coat gums (and on unsized paper). I'd probably not paid much attention to it before, when I wasn't attempting gum, but reading it now-- it's been really helpful. It's in a different issue, though, which I had followed, that includes those step-by-step instructions and illustrations, which is the one that probably talks in more detail about pre-shrinking/sizing-- though not sure.It took me a while to find the mention, and when I did I was annoyed with myself -- I'd done exactly what I accuse the "experts" (ESPECIALLY the digital experts!) of doing when they write up their info: It's in their head, so they don't realize it's not on the page. I prided myself on catching that stuff for articles in P-F: The info wasn't in *MY* head, tho I knew know enough to know when it was missing (which yr average "editor" doesn't _ it's *all* gibberish to them). The shrink info turned out to be in Issue #9, page 49, "Gum Buckramate -- and other ways to re-register a gum print." There's a variety of good and useful info (she said modestly), but I didn't say how long I'd soaked the paper for my cold water test, briefly mentioned as follows: "...Standard instructions call for the hottest possible water. My tests show that a long soak in cold water gives the same shrinkage as hot, even boiling, water, and is a lot easier..." The figure that comes to mind now is three hours, but, fortunately, the test is very easily done: Take, maybe 3 print-size sheets of the paper you want to test, and draw a light pencil line (or simply place 2 marker carets) on two sides, one the length and the other the width, because you can't (or I can't) be sure in which direction the final factory roller/pressing was done, which would be the direction doing the most shrink. Measure carefully and write the length in each space. (But make the test more or less the length of the side -- measuring the shrink over 2 inches obviously isn't as good a test as measuring over, say, 21 inches. Then soak the paper in water from the tap (separate trays is probably safest -- friction from papers under or over each other might conceivably inhibit the shrink -- or what can go wrong will go wrong). Soak one for, say 3 hours, another for maybe 6 or 8 hours (I like to do one for the outer possibility) or whatever seems likely to you. The 3rd sheet is the "control": In a separate tray, cover this sheet with the hottest water you'd use in a hot-water shrink, and leave for whatever time you usually leave it. In fact when I did hot water shrink in a cold room (ie, winter) I used to replace the hot water as it cooled at least once with newly hot water. Then dry the sheets as you usually dry them (hanging from one end, lying on a blotter, or screen, or whatever), and let them REALLY dry (maybe 2 days in humid weather?). My hunch, by the way is that this test might be worth doing even if I could tell you the time of my room-temp shrink for sure: papers vary and it makes sense to double check my findings on my paper with my methods against yours. And finally, I note that unless you work in a temperature-humidity controlled room (which as I recall is the way Steven Livick worked) there is no way your register can be exact for each recoating -- which is, by the way, another reason I don't use register pins on the edges of the print (aside from their being such an everlasting pain in the butt). I re-register from the center of the image and if it so happens that the outer edges are a little off -- well, that's Outer Mangolia and if we were uptight about things like that, we'd probably choose a different art form (maybe rocket science). I re-register on a light table (regular fluorescent bulbs -- I have a drawer that pulls out from under my copy machine, but it could be tucked anywhere). That is, NOT a UV exposure table, tho that wouldn't expose my emulsion from the back, no matter what some jerk books claim (I've tested leaving the coated print on those bulbs for a full hour and -- NADA !), but unless you're wearing UV proof glasses and even if you are... *not* a good idea to look into that light. I'm moved here to repeat what I'm sure I've said elsewhere: testing is good, because unlike "art" (of which I've probably destroyed as much as I've kept) there's no such thing as a failed test -- they ALWAYS give you information. OK, enough... have fun ! J.
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