Sorry to bring this thread back. I ordered my glyoxal from photographers formulary. However, you can use formalin, which is sold at aquarium supply stores in place of glyoxal.
combine 25ml of formalin to 1000mls of distilled water (outdoors) and submerge your paper coated with (plain) gelatin for a minute or two then hang to dry outdoors for at least a day. Formalin contains formaldehyde which is flammable and poisonous. Wear nitrate gloves, and definitely work out doors.
Glyoxal is my preference because it is slightly easier to work with. The jurys still out if it is less dangerous, so I take every precaution.
Regarding printing on an unglazed tile as per Nicholas suggestion, I have made a platinum print on a green fired plain white tile and then put clear glaze over the print and refired it. I did that about 20 years ago and I still have it today in use as my coffee mug place on my counter. Very durable.. but light in tone.
Alex, when you say "submerge your paper" above, can i read "submerge your tile"? This second advice from you is quite different from your previous one in this same thread!
If possible go for the glyoxal version, the formalin is pretty bad for you. But if you are on a tight deadline, it'd be quicker to acquire some formalin because it can be found locally. If you have chrome alum around you can use PE's recomendations as well. My poorly communicated point was that for a subbing layer, knox gelatin seems to be sufficient in place of photo-grade gelatin.
Yes you can substitute the tile for paper in the above post. Haha :)
Thanks Alex, i will try the first recipe you mentioned (glyoxal + gelatin, heated). Instead, i will replace the glyoxal with formalin. Happy New Year!
Do NOT heat cyanotype chemicals - see below
Originally Posted by Nicholas Lindan
Releases hydrogen cyanide gas if heated, if hotacid is added, or if exposed to strongultraviolet light (McCann, 1994)