Hey Steven, thanks for response.
Since I posted that question in Photoshop forum, I’ve been working with another method of making my exposures.
I’m not familiar with the plates and material you’re using. I’m using ImagOn film. Earlier this summer I took a workshop with Keith Howard, who is familiar with printmaking with this film. To make plates, I adhere the film to PETG plastic sheets which are 0.03 inches thick. I bought the plastic at Laird Plastics in Seattle (I think they have other stores in US). They had pre-cut "seconds" about 3×4 feet at a very good price, which I cut to the size I need.
I do have an aquatint screen from McClain’s printmaking supplies, at a better price than at Dan Smiths: <
http://www.imcclains.com/catalog/blocks/aquatintscreens.html> A printmaker named Elizabeth Dove also sells them: <
http://www.elizabethdove.com/screens/index.htm>
However, for photos (or any digital image really), Keith teaches a way to make them without a "duel" exposure involving an aquatint screen. The basic idea is to put the grain of the aquatint directly in the image. Some of the steps in doing this are to:
Start with an image that’s about 100-200 PPI resolution (I use 180 PPI since it divides evenly into the 720 DPI output resolution I’m using with my inkjet printer)
Use a printer that can print all black inks and not make up the black from a range of colors
"Flatten" the contrast in the image, making blacks lighter and sometimes light tones darker. For my images, I’m working with Curves, reducing 100% black down to 70% or even lower, and 0% whites to about 10-12% — this is where I’m doing most of my experimenting, and is really the key for me to getting a full range of tones–black to white–from my prints (I’m having to work more with the curves than this, and they are not linear).
Use transparency film that is specifically for inkjet printers (I was using a film brand from www.inkjetart.com called InkPress), but I’m getting samples for other brands, to see if I can get good results and get the cost down.
That said, we of course had success with this method while we were in the workshop, but once I got back home I couldn’t duplicate it. After many failures–and calling into question every part of the process, including the exposure unit, the strength of my developer, the transparency film, the paper, the ink, the press–I figured out that my Epson R2400 printer was the culprit: though it makes fine prints on paper in black and white, it is somewhat limited in the controls it offers. For example, in order to get prints with mostly black inks, you have to use the Advanced B/W mode, which only prints out at a finer resolution (1,440 DPI at least) that doesn’t give you the "aquatint" grain in the image. If I printed at a lower resolution, the prints came out crappy. I also tried converting to bitmap (using diffusion dither), but the images came out really grainy, and I was plagued with some of the same problems with the printer.
Enter Quadtone rip. I’ve downloaded this program for printing B/W prints and it gives me much more control of what I’m doing: I can print at 720 DPI output and the program doesn’t assume that low resolution mean crappy output. I can control which inks the printer uses and have been experimenting with using mostly black ink, a little light black ink, and the color inks and light light black turned off. So between this control and working with Curves, I I’m pretty close to getting the results I want. (As an aside, the studio I work in is a half hour drive, half hour ferry ride and 45 minute walk to get to; so there is lag time between what I’m doing at home with my inkjet and the results I’m getting in the studio.)
I have one thought on your exposure unit. I’ve heard that black lights and also fluorescent type bulbs will not give you good results. I’m not sure why, except that I understand the light rays from fluorescent tubes may be too random (and I really don’t know what I’m talking about here!). If you’re getting good results, fine, but if not, this is one thing you might do a comparison with.
So, that’s it. Hope I didn’t ramble too much and that you find some of this useful.
Best, David.
