Re: Kallitype exposure and negative dmax

Re: Kallitype exposure and negative dmaxThanks for the tip on the dichromate replenishment. However, wouldn't having more dichromate in the developer worsen my problem?

  ----- Original Message -----
  From: Sandy King
  To: alt-photo-process-l@sask.usask.ca
  Sent: Friday, December 05, 2003 7:39 PM
  Subject: 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: Sandy King
      To: 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 22:35:31 2003