Since it is sulfuric acid, I get it at the local battery store in quart containers. Dilute 4 water 1 acid.
According to the MSDS, it is also 15 - 20% (by weight) Aluminum Sulfate.
“Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”
Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2
if you run into a bind and the kodak hardener runs out
look for sprint alum hardener .. its cheap and works well.
i use it in my fix baths when i process plates, and when
i process plates in it by mistake. it doesn't work as a developer very well