Kallitype contrast control

[Pete Suttner]

I've been playing with digital negatives and printing kallitypes with Bostic & Sullivan kit. Some dismal failures, but also a couple killer keepers.

The instructions with the kit read "advanced printers adjust contrast with small additions of 2% ammonium dichromate. If one drop is too strong dilute the solution". Not very helpful. Do I add the dichromate to the sensitizer or the developer? Dilute with what? Kool-aid?

Anyway, thanks in advance for your help.

Pete

[Jason Greenberg Motamedi]

It goes into the developer.

[Pete Suttner]

Thanks - back at it tomorrow....

[sanking]

Try this.

"Contrast can be controlled by the addition to the developer of a few ml of a 5% solution of potassium dichromate solution. The practical limit ranges from as little as 1 ml per liter of developer up to about 16 ml per liter. This allows the use of negatives from a DR as low as about 1.2 to a maximum of about 2.2. If too much dichromate is added, printing times will increase considerably and the image will take on a granular look. For negatives that have been developed to a DR of about 1.8 add about 2ml of the 5% potassium dichromate per liter of developer.

The developer can be reused, but it must be replenished. I recommend replenishment at the rate of about 100 ml of developer for every 100 square inches of print surface developed. If the developer is not replenished the accumulation of ferrous iron and chemicals from the paper will make it increasingly difficult to clear the print during processing. This will result in an unpleasant stain in the areas of the print that were coated but masked in printing. The stain is not only unattractive, but will also decrease the permanence of the print because it consists in large part of residual ferrous iron that has been converted to iron hydroxide."

The above is from an article I wrote some years ago on printing with kallitype. http://www.sandykingphotography.com/...litype-process

Sandy