Anyone out there have a link to an article on sizing your own paper?
Here is an excerpt from my gum-platinum workshop manual that may be of some help:
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Size Matters
The platinum print should be re-sized for optimum results with the subsequent gum layers. Sizing seals the surface of the paper and minimizes pigment staining problems and aids in smooth, even development. I've tried several different methods and materials for sizing, and have come full circle to a standard gelatin size with hardener. The hardening can be done as a separate step after the sizing has dried, but this is just more work. I prefer to add the hardener directly to the sizing as described in Livick's book (see References). There are times when you may want some pigment stain on a first gum coat and you can accomplish this by not sizing until after the first gum coat (more on pigment stain later).
To make 2% to 4% gelatin sizing;
- Add 2 gm to 4 gm gelatin per 100 ml distilled water. Allow to 'bloom' for 20-30 minutes
- Heat to no more than 140oF
- Optional: Can add ethyl alcohol (Everclear) to reduce sparklies at a ratio from 15:1 to 20:1 gelatin to alcohol
- To harden and preserve the gelatin add formaldehyde (37%) or glyoxal (40%).
WARNING: Formaldehyde is a hazardous chemical and must be handled appropriately. Skin, eye and breathing protection are a must.
We will use glyoxal as a less hazardous substitute for formaldehyde. It works well, but you should print on it soon after sizing otherwise the sizing may yellow.
Add the hardener at the rate of 1 ml per 1.5 gm of gelatin. For example:
100ml of 3% sizing contains 3 gm of sizing. To this add 2 ml of hardener.
100ml of 4% sizing contains 4 gm of sizing. To this add 2.7 ml of hardener.
or:
6 drops hardener for every 10 ml of 3% sizing
8 drops of hardener for every 10 ml of 4% sizing
Coat the paper quickly with a glass rod or hake brush or a combination of both. The gelatin soon becomes sticky as it cools, so work quickly.
Allow the sizing to dry completely. The paper is now ready for adding the gum bichromate layer(s).
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It's really pretty easy to do and doesn't take much time if you batch it. Be careful about heating sizinig in a microwave. They don't heat evenly and if you overheat it, you'll render it DOA. I prefer to heat my sizing on a mug warmer if I'm only making a small quantity, or in a double-boiler type setup on a small electric burner if I'm making larger quantities.
Good luck.
Kerik Kouklis
www.kerik.com
