U of S | Mailing List Archive | alt-photo-process-l | Re: bichromate gum

Re: bichromate gum

On Sun, 13 Jul 2008, Christina Z. Anderson wrote:

But, Kosar shows the speeds of the different dichromates with albumin, gum, and process glue and there are some variations in speed with the colloid used I find quite interesting--albumin being slower to harden with both pot and sod than the other two colloids although with am di it is not (53). This may also explain some differences of opinion as usual--different gums might react differently due to pH or some other factor. And the weird thing is that with gum and process glue, it appears from his chart that sod and am are equal in speed, but with process glue am di is faster. However, in practice when one uses a 5 or 6 minute exposure time, these variations probably don't matter because one always suits practice to what's on hand.
Good grief -- I wouldn't trust Kosar, or anyone else including my fairy godmother to give -- or show -- me that data... There is NO substitute for your own tests with your own ingredients (including the paper, your body pH and your personal virtue). Since those tests with a 21 step or whaever, are so much easier than reading Kosar (not to mention FINDING it) and especially since as I recall Kosar never said much besides "probably," or "presumably" about anything, ESPECIALLY about gum printing. Most of what he talks about is carbon -- and simply describes his own surmises from tests by OTHER people.

That's info ???

Of course I've done this rant about Kosar a couple of times in the past (which may be why some alt lister snuck into my house & stole it).

Incidentally the tests I did with na di those many many years ago were with the chemical sent to me by someone on the list, from California if memory seves, and who knows what California does to chemicals...NY may not be as mean -- or meaner !