DonF
Member
I have a Beseler 23CII-XL with the older Dual Dichro head (external stabilized power supply). I have it set up with the condensers and the conic light integrator in the head, although I have the diffusion kit as well.
I have started experimenting using the enlarger for variable contrast printing. I find that I cannot get sufficiently long exposures at the optimum lens f/stop without using the dichro filters as a neutral density filter. For example, I may set the yellow-magenta-cyan knobs (marked 1 to 200 each) to 60-60-60 to give an attenuated white light for longer exposures. This seems to work fine.
I have two questions about using the filters in this way.
The first question is whether the calibrations on the filters are linear. For example, the Arista Edu VC paper insert recommends a 10M (magenta) setting for grade #2 for "Beseler" enlargers (no model given). If I dialed the Y-M-C knobs to 60-70-60 would that give me the same (except for exposure time) contrast as 0-10-0? In other words, are the scales on the dichro head theoretically linear.
Similarly, if I achieve a good exposure using the setting 60-70-60 setting (hopefully contrast grade #2), could I change the contrast without altering the exposure by setting the dials so that the sum of the Y-M-C setting remains the same while creating the same offset of the needed color? So for example to change from Grade #2 (60+70+60 = 190) to Grade #0, with an Arista-recommended setting of 80Y, could I set the knobs to 116+37+37=190 (Yellow is about 80 more than Magenta and Cyan and the sum is still 190) and expect the exposure to remain unchanged.
Regards and thanks for any insight,
Don
I have started experimenting using the enlarger for variable contrast printing. I find that I cannot get sufficiently long exposures at the optimum lens f/stop without using the dichro filters as a neutral density filter. For example, I may set the yellow-magenta-cyan knobs (marked 1 to 200 each) to 60-60-60 to give an attenuated white light for longer exposures. This seems to work fine.
I have two questions about using the filters in this way.
The first question is whether the calibrations on the filters are linear. For example, the Arista Edu VC paper insert recommends a 10M (magenta) setting for grade #2 for "Beseler" enlargers (no model given). If I dialed the Y-M-C knobs to 60-70-60 would that give me the same (except for exposure time) contrast as 0-10-0? In other words, are the scales on the dichro head theoretically linear.
Similarly, if I achieve a good exposure using the setting 60-70-60 setting (hopefully contrast grade #2), could I change the contrast without altering the exposure by setting the dials so that the sum of the Y-M-C setting remains the same while creating the same offset of the needed color? So for example to change from Grade #2 (60+70+60 = 190) to Grade #0, with an Arista-recommended setting of 80Y, could I set the knobs to 116+37+37=190 (Yellow is about 80 more than Magenta and Cyan and the sum is still 190) and expect the exposure to remain unchanged.
Regards and thanks for any insight,
Don