I would think that with the use of a densitometer that the central density as opposed to the edge density could be determined. I would determine this with the normal development time for the film which you now use. I would then seek to gain this degree of density gradient with a lithographic film. I would presume that a lithographic film would prove the most advantageous to your desired objective since it would not contain the consideration of film granularity. I have used the Aristo half tone lithographic film available from Freestyle for masking of negatives and under proper dilution with Dektol a low contrast negative can be obtained. Additionally the thinner base of this film would stand you in better stead. Making a sandwich of this film negative and two pieces of glass or thin acrylic would allow you to use this in a Cokin type of film holder. If you desire the dilutions that I use for my masking, you may email me and I will get those to you. Good luck.
Regards,
Donald Miller
John Cremati <[EMAIL PROTECTED]> wrote:
I wonder if you were to shoot a light grid or evenly illuminated fabric, or illuminated wall , and used that negative which would show the light fall off for that lens as the basis to create the center filter.. ?
