variable contrast paper VS cold light filteringgreenspun.com : LUSENET : Large format photography : One Thread
Hi there knowledgeable printers. Ilford suggests a CC40 filter when using a cold light head with their Multigrade paper. That is what I use presently. The contrast grades are not evenly spaced. They seem to bunch up from no2 to no6. Somewhere on Ebay there is a color picture of an Aristo 14x14 head that looks very green to my eyes. Would a green CC filter provide better results than a yellow CC filter? Please help!
-- Pierre Robitaille (email@example.com), June 06, 2002
Pierre: Maybe someone who HAS been able to get this to work can help, but I tried it and no amount of filtration could tame the contrast I was getting with my Aristo head. I called Aristo and they more or less said you can try making the light more yellow, but relamping with the V54 tube was the way to go. They were right, it works great with the V54 tube. The light color goes from white with a blue tint to an intense aquamarine blue. It does allow for small and predictable and evenly spaced changes in contrast. Good luck.
-- Kevin Crisp (KRrisp@aol.com), June 06, 2002.
I use Ilford MG papers and Gekko VC B & W papers on a Zone VI Beseler 45mxt cold light head. No filter used to correct the cold light color. Have had no problems with either paper. I use a standard set of Ilford VC filters to control contrast. They all work fine on either paper - my prefered paper is the Gekko.
I've seen the CC40 at auction on Ebay currently. I have no idea what advantage it may provide to your printing. If you get one, please let me know if it improves your contrast response for your printing.
Good light. -Steve
-- Steve Feldman (firstname.lastname@example.org), June 06, 2002.
Older cold lights are blue heavy, so contrast tends to be higher with VC papers. Also, the filters are designed for other light sources with different spectral emmission properties - the problem you describe is typical, with uneven spacing between the filters. Using CC40 filters etc might help but will not obviate the problem - the problem is in the spectral emmision of the tube in your cold light. If you don't want to go to the expense of a V54 tube, try using split filtering (i.e., one exposure through the number 5 filter and one through the 0 filter) to get any intermediate grade you want. You can avoid the problem of uneven grade spacing that way. Cheers, DJ
-- N Dhananjay (email@example.com), June 06, 2002.
Contact Fred Newman and ViewCamera.com. You can make 8x10 prints from a step tablet that he will read and put through the BTZS software. He will send you the actual contrast grades for the filters and you will be in business as long as you keep the same paper, light source, routines. Give him a call. He is VERY knowledgeable and accommodating. This is the best testing procedure, straight-forward, efficient, sophisticated and reliable.
-- David Meriwether (firstname.lastname@example.org), June 06, 2002.