Quote Originally Posted by DREW WILEY View Post
Anyone who thinks the bleach is innocuous is a fool.
It's basically con sulfuric acid, and will do the same thing to your lungs! The amateur powdered version
was sulfamic acid - not quite as bad, but still strong enough to give you emphysema for life if you're
dumb enough to repetitiously inhale it.
Anyone wanting to deeply inhale any kind of photo chemistry should be kept away from dark rooms as long as this desire persists. Yes, dye bleach is very acidic which means don't get it on your skin, don't rub it into your eyes and don't eat it. Besides that it contains a bleach catalyst which may or may not be carcinogenic, which gives you another reason to neither touch dye bleach, nor eat or rub it into your eyes.

I would recommend against doing Ilfochrome in open trays (remember: complete darkness!), but in closed tank rotary processing there is little chance you get in direct unintentional contact with dye bleach.

Quote Originally Posted by DREW WILEY View Post
Velvia is no more a problem on Ciba than any other transparency film. If it's on the image, I can print it. But you better have an intense colorhead to print through a .90 mask on a slooooww paper like this.
The big issue with Ilfochrome is that it transfers images more or less 1:1 in terms of contrast, but that slides have much more dynamic range than Ilfochrome paper. This issue is amplified with emulsions like Velvia which are contrasty to begin with, and less of an issue with lower contrast emulsions like Astia. With masking, or in special cases with dodging&burning you can work around these issues, but I personally prefer avoiding issues to working around them.