Hi Brian,
I make it from scratch. Raw chemistry from Artcraft.
As I mentioned above, it's a variable sepia toner. The "variable" part comes by altering the alkali in the formula. The more alkaline the toner, the browner the tone. The less alkaline, the yellower. It's a graceful system, and gives you a lot of control over your output. There is also a variable bleach system which accompanies these toners, but I haven't had much luck with that. A standard Potassium Bromide + Potassium Ferricyanide bleach gives me the best results.
For the toners, there are only 4 chemicals needed: Thiocarbamide (Thiourea), Potassium Carbonate, Sodium Carbonate and Sodium Hydroxide. Of these, care must be taken in handling the Thiocarbamide and the Sodium Hydroxide. What I do is mix a 10% solution of these two chemicals, and use it as a liquid concentrate. That was I'm not handling the dry chemistry on a regular basis. When I do handle the dry chemicals, I wear a suitable repirator, gloves and goggles.
The formula are:
Toner 1
Thiocarbamide 3.0g
Sodium Hydroxide 6.0g
Water to make 1000ml
Toner 2
Thiocarbamide 3.0g
Sodium Carbonate 45.0g
Water to make 1000ml
Toner 3
Thiocarbamide 3.0g
Potassium Carbonate 48.0g
Water to make 1000ml
The bleach that I use is:
Potassium Ferricyanide 22.0g
Potassium Bromide 25.0g
Water to make 1000ml
The 10% solution of Thiocarbamide is brilliant, as I'll just pour out 30ml of it and I'm set.
The toner once made lasts for a few days in my opinion, but results start to change as time goes on. I usually make enough for a session and pitch it.
This system was designed for the Dupont Varigam papers, but works well with anything. I particularly like Toner 1 on IMG IV, and IMG WT.