Re: Pd with dichromate contrast control
Camden, With dichromate contrast control you can add the dichromate either to the FO + PC before you coat the paper, or to the developer. I have done the latter. You will need to replenish the developer with fresh solution + dichromate as you make prints. What I have found is that adding about 2ml of a 5% solution of potassium dichromate to the developer will give about the same exposure scale as the use of Arentz's 2s solution, i.e. about log 1.8 or 1.9, if measured from maximum black to paper white. If you work with negatives of widely differing DR you would need to have on hand a number of bottles of developer, each with a different amount of dichromate. In this circumstance it might make more sense to add the dichromate directly to the sensitizer. I know this works but don't have any details to share. Sandy King At 10:18 AM -0700 12/14/06, Camden Hardy wrote: I've been using the Dick Arentz method of pd contrast control with various concentrations of the Na2 solution. I'd like to try printing pure palladium with ammonium dichromate for contrast control, as I've heard someone mention in the past. So my question is, how does one method translate to the other? What kinds of quantities/dilutions of am. dichromate would I need to use to get comparable contrast results to Arentz's 1s/2s/3s solutions? I realize this is an apples/oranges question before asking it, but I'm having trouble finding a better analogy. :) Thanks, Camden Hardy camden[at]hardyphotography[dot]net http://www.hardyphotography.net
|