Odd Kallitype printout behavior

[John Lockhart]

I have been learning the Kallitype process for a couple of months, and I recently noticed a strange change of behavior in my printing. I thought it might indicate a flaw in my process or suggest something I could be doing better. Even if it is inconsequential I am simply curious to know what is happening.

I use the standard 10 percent Silver Nitrate and 20 percent Ferric Oxalate coating on Stonehenge paper. When I first started printing I used a ‘lizard lamp’ as a UV source. This is one of the lamps you can obtain from a pet store that is designed to give your reptiles enough UV for proper absorption of mineral and other nutrients. When printing with this lamp the paper printed out as I have seen it documented by others. There was a faint brown purple image that became much more dense when developed.

This was a very cheap lamp. When it broke I replaced it with a bank of four 24 inch blacklight bulbs. These are still aren’t the best lamps, but better than the first. As soon as I moved to the blacklight bulbs the paper would print out to a very dark brown. The image is so dark out of the UV box that when developing in a brown developer like Sodium Citrate the image clears up in the developer but doesn’t become much denser.

Once I us gold toner on the prints they look about the same. However, I am still wondering what causes the difference in tone and whether this is an indication of something good or bad about using blacklight bulbs for printing.
I was wondering if anyone has had a similar experience or any insight into what the difference in print out means and what causes it.

I may post of a sample image if I get any responses about this.

Thanks,

- John

[Loris Medici]

John, if the results exactly match (with the same stock solutions) then I'd suspect it's something about the relative humidity of your paper / workplace. To my knowing Kallitype shouldn't give too much print-out, but high humidity increase the amount of print-out for sure...

Also, I suspect the new BLB lamps give more energy in the <400nm region. (Probably peaking something around 350-360nm...)

Anyway, I'll let this to people with more experience with Kallitype. I'm a Vandyke person myself and I don't have any Kallitype experience other than a couple of test tablet / digital step wedge printing...

[R Shaffer]

Ciao John,

I use extra cheap ( 18" ) BLB bank for kalitypes. Mine always have brown shadows & yellowish highlights. The coated areas of the paper that are not under the negative are very dark brown and usually lighten from solarization when I develop. Although they usually un-solarize when I tone in pd.

Is it possible that you are overexposing?

Also, if you are using a digital negative, changing light source will change your curve.

Also what Loris says, changes in humidity will effect the density of your black.