Hot drying paper before exposing
I'm going to start with hand-made photo paper, i.e. photographic emulsion spread more or less evenly on some nice fibre paper. Recently I prepared a couple of papers, and they - as one may expected - curled, curved and waived heavily. This may cause problems when enlarging or contact-printing. My idea is to wash and hot-dry them before exposing. Yet I am not sure if hot-drying doesn't fog the emulsion. Any experience?
Washing the coated paper will likely alter the emulsion resulting in speed change, fog, or instability. Heat will make matters worse.
If your paper is showing severe curl/distortion, you might be applying to much emulsion and/or the paper is inappropriate for the job. I use Canson or Strathmore Bristol; with a thin coating ( 5 mil) it shows only minor curl.
Things you can try:
Pre-soak and dry the paper before coating. Drying under pressure should help to keep it flat.
Tape or pin your paper to a clean flat surface (glass, plastic) before coating to lessen curl and waiving.
This is what I do w/ watercolour papers that need to be coated w/ gesso for painting w/ acrylic or oil paints (should be the same principle). Wet the paper thoroughly by soaking it in a tub of water for 20-30 minutes. Then, put the wet paper on a flat surface w/ a towel laid down first, place another towel on top of it, and press down firmly to blot some of the water out. Let it sit for a spell so that a lot of the water has been blotted out, and then staple it all around to a sturdy 1/2" or 3/4" piece of plywood. Use lots of good, heavy duty staples. Next, when the paper is still somewhat damp, brush your emulsion coating on it. As the paper dries fully it will shrink, and since it's stapled to the board, it will pull itself taut like a drum. Once it's dry, remove the staples, or cut it off the plywood.
Last edited by momus; 11-18-2013 at 02:54 PM. Click to view previous post history.
This is good advice. Don't wash it and use a paper with sufficient wet strength to cope with the job. If you are using watercolour paper you need to size it before coating, which means pre-soak and tape it down with gum strip along each edge when wet and let dry.
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