Re: Photopolymer Plate Options
Mark, and Jon, Keith, Susan, Nancy, etc. etc.!
Thanks for this message, below, Mark. I had gone to Jon's site previously and missed this entirely.
First, Jon, thank you for taking the time to do such a nice, informative, sharing website on photopolymer gravure. I've got a bunch of books on the process and find your website even more informative because you've experienced the frustrations with plates as I have. Dan Welden's book is wonderful as are other ones, but it doesn't deal as much with photographic imagery as I would like. Dan is not a photographer and is not a computer whiz, to put it mildly. So it looks to me like you, Don Messec (?), David Hoptman, Keith Taylor, and very few others have taken this essentially letter press stuff and made it continuous tone. I can imagine why so few--expensive!!! It is driving me crazy enough to want to buy a $3000 Amergraph ULF-28 unit!
I checked out your curve and find it fascinating that you and I (my using solarplate, your using Toyobo) have come up with pretty similar curves in a sense--probably as close to straight line as I have derived in any process through PDN (except, maybe, carbon pigment gum is pretty straightline, too). So I find the material fascinating that it is so straight line instead of, say, cyanotype which needs great curve modification to print within a narrow range of tones. Mind you, I've been deriving this curve over the last 2 solid months and, as you, wasting lots of money and time. My biggest problem was having to rethink backwards continually--because you are going from a positive to a negative to a positive, blah blah blah. So great room for operator error.
I find it also, again as I said before, fascinating that it hardens from the bottom up, contrary to gum theory which says it hardens top down (not that the two have anything in common, solarplate being from what I can tell nylon, BUT PVA, too).
Second, I went back over my Dan Welden's book, which I love, and he says a very interesting point in there which I would love to see if you all, too, have found this in practice. I think this applies to II Test and/or Expose the Plate on Jon's website: (p. 87-88, long) " In general, with the double exposure technique the best results are obtained by using equal times for both exposures, but you can manipulate the relative times of each exposure to influence the final impression. If you increase the exposure time of the screen relative to the positive, say 2 min 15 sec for the screen and 1mn15sec for the transparency, lighter tones are strengthened, while some darker tones will become darker. The overall effect is to darken the image and is a useful approach for very light transparencies....Yu can also do the converse and decrease the time of the screen relative to the positive, say, 30 seconds for the screen and 1mn30sec for the transparency. With this type of exposure you may gain a better range of midtones, but lose some lighter tones. The overall effect is to lighten an image. Deep grooves and areas of open bite can form, and, by fine tuning the relative times of each exposure, you can control the extent of open bite."
Last night I exposed 12 of the same image on a plate at aquatint exposures of 1, 2, 3, and 4 minutes and positive exposures on top of 9, 4, and 2 minutes (curved image). I will run into town and print today to see how the ratio of the two changes the look, but any thoughts on this are appreciated, e.g. what percentage do you all find of the whole image do you make the aquatint exposure.
If I ever master this, and bromoil, then I will have "arrived". At least with gum it is only a wasted piece of paper and no trips to town to use a press.
----- Original Message ----- From: "D. Mark Andrews" <email@example.com>
Sent: Friday, February 16, 2007 9:48 AM
Subject: RE: Photopolymer Plate Options
Christina, I accidentally deleted you other post, but you can download Jon Lybrook's curve from his site for the KM73 plates: http://www.lytescapes.com/procedures/polymer_photogravure.html