Glop Shelf life
What is the expected shelf life of glop?
Would it be best to coat a bunch of sheets and store them not sensitized of course, or leave it in the pitcher and warm to coat as needed?
The reason I am asking is I have to fit photography in when I can but really want to try carbon.
This is one of those times when I am reminded that the terms, "Wise Man" and "Wise Guy" have completely opposite meanings. ;)
I am lucky in being able to tame the nasty side of gloppies for my cyanotype sizing works. I inherritted a whole ton of organic and inorganic chems from a biotech r&d lab after a bankrupcy interruption in operations.
I have a jar of very carefully stored, pretty potent, biocide that I mix (under very carefully controlled conditions) as a 1% solution, and then mix that as a 10% solution so I am down to a 0.1% solution. Add 20mL of that stuff to the unhardended gelatin, stir it in, and put the gelatin in the fridge.
14 months later, and there is still no sign of ucky goo ilike usually loves to grow in the gelatin.
No potent biocide at my disposal, and not sure I want to use one. Just the name gives me the creeps.
Bleach? Rubbing alcohol? Everclear? All would be pretty potent "biocides" I'd think.
Originally Posted by mark
I don't have the notes at hand - looked at the card I mixed from last night and I worked out both of these options, but forgot tobring it to work this morning.
I used either Chloramphenicol or Cetylpyriduim Chloride
Do yourself a favour and pour your tissues right after you make glop. Store the dried tissues in a large ziplock bag. Store in the freezer.
I have stored glop with a bit of thymol added as a biocide for 4 to 6 weeks in my refrigerator. I didn't notice any difference in the tissues I made with it. Generally though, I did as Andrew recommends and poured the tissue right away and stuck any tissue I wouldn't be using within a few weeks into the freezer.
If I remember correctly, I got thymol from Photographers Formulary and dissolved the crystals in alcohol making a 30% solution. A few drops added to your glop will keep it from turning into a science project in your refrigerator. Thymol is an ingredient in many brands of mouthwash. I have read posts by others saying that they have used mouthwash as a preservative - Never tried it myself.
My glop lasts a couple days (kept warm) if I push it, but one might as well pour tissues from all the glop one makes, and make fresh glop for more tissues. My attempts to keep glop in the refrigerator has resulted in smelly biological experiments. I make two or three batches of glop at a time (usually 850ml per batch). Each batch makes three 14x17 tissues.
I dry tissues on cardboard, stuck on with push pins. Once dry (two days in my climate) I just stack the cardboard and use as needed -- usually within a couple months. The push pins keep the surfaces of the tissues from touching anything. They all print fine, but I do notice that the fresher the tissue, the easier the non-exposed gelatin melts...but never to the extent that the gelatin is difficult to melt.
If one's climate is dry, then one might have some problems with the tissue curling and/or cracking. But with a RH of 60 to 70%, that is not a problem here. So Andrew's suggestion of bagging the tissue would be good in areas of low RH.