Re: Kallitype exposure and negative dmax

Michael,

I always try to put back into the used developer exactly as much
dichromate as was expended in the amount of lost or discarded
solution. My reasoning is that if I do not do this the amount of
dichromate in the solution will eventually stray considerably from
the original amount and there will be no consistency in contrast in
my prints. Basically I replace the dichromate by the drop. For
example, assuming you are working with a 1000ml bottle of developer
which contains 2ml of a 5% potassium dichromate solution, and your
developing session uses up 100ml of solution. 2ml is about 48 drops,
so I would replenish the lost 100ml of solution with 1/10 of 48 drops
of the 5% potassium dichromate solution, i.e. 5 drops.

Sandy

>Sandy,
>
>Currently I use very little dichromate in the developer. It's hard
>to measure because I am replenishing the developer with fresh sodium
>citrate and usually throw in a few grams of 5% dichromate only here
>and there. I'd guess that the dichromate level is on the order of 1
>gm/liter or less.
>
>When I first started making kallitypes I used no dichromate and
>didn't see the problem that I now have, although there were even
>worse problems with the prints not clearing well. The clearing
>problem was seemingly solved with the addition of dichromate.
>
>Regards,
>
>Michael
>
>
>
>
>----- Original Message -----
>From: <mailto:sanking@clemson.edu>Sandy King
>To:
><mailto:alt-photo-process-l@sask.usask.ca>alt-photo-process-l@sask.usask.ca
>Sent: Friday, December 05, 2003 4:27 PM
>Subject: Re: Kallitype exposure and negative dmax
>
>Michael,
>
>Working back through your process of measuring the density before
>inverting the negative and then printing is too complicated for me.
>In my work I aim for a final DR of 1.8 on the negative and adjust
>the amount of potassiumn dichromate to compensate. A negative with a
>final DR of 1.8 generally allows me to print the full scale of the
>negative when adding about 2-4ml of a 5% solution of potassium
>dichromate per liter of developer.
>
>The cause for your problem is as you have surmised: i.e, the DR of
>your digital negatives is too high. Therefore, the final solution
>you propose is correctly reasoned. However, you could also extend
>the tonal scale by printing to the same DR and using less potassium
>dichromate in the developer. If you tell me how much you used in the
>situation below I can suggest an adjustment that might solve the
>problem without having to re-print the negatives.
>
>Best,
>
>
>Sandy
>
>
>
>
>
>
>
>>I'm working on some kallitype images using printed digital
>>negatives. I've been using a dmax curve of 1.8 on the images
>>before I invert the image and print the negative. The resulting
>>prints have the shadows becoming overexposed before the highlights
>>have been exposed properly. If I expose for the highlights,
>>the blackest parts of the print get overexposed to the point of
>>solarizing during development. If I expose the black correctly,
>>then the highlights are underexposed causing an ugly posterization.
>>Will using a lower dmax on the negatives correct this
>>problem....say 1.5 - 1.6 or so?
>>
>
>
>Regards,
>
>
>
>Michael
>
>
Received on Fri Dec 5 20:42:45 2003