Glyoxal amounts
About a year ago, in the wake of a hurricane, Marek reported some good experiments by which he demonstrated (by coating glass with gelatin containing various amounts of gelatin, allowing it to set, and then immersing it in warm water to determine how much the gelatin softens/swells) that the amount of glyoxal required to harden the gelatin to where it will swell but not dissolve is 1/10 what is usually recommended. I've gone on sizing paper using the recommended 15 ml 40%stock solution/ liter,of gelatin solution, or 3 cc in 200 ml gelatin, but the last time I sized, I cut back alittle, just to see; I used 1 cc in 200 ml instead of 3 cc, or in other words I cut back to 1/3 of what I'd been using, but wasn't quite ready to cut back all the way to 1/10. My results were not good; I sized two different papers (Lanaquarellle and Arches bright white) and have been getting heavy staining on the second coat with both papers. Not a refutation of Marek's findings, but just more data for our database. Marek, have you found that your findings on glass have translated to practical success on paper? And if so, which papers? In the meantime, I'm going back to the traditional formula, which has always worked for me. Katharine
|