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Negatives are often low in contrast 
Elliot  19:33 7 Dec 12 
After using the BTZS system for some time, I believe that the Plotter files that are exported to ExpoDev might have been written in Plotter using a paragigm such that negatives are exposed and developed to a contrast level that is often too low. I am using graded paper ( either silver chloride or contemporary Ilford ) and I find that my negatives are often too soft. I am a careful worker and doubt that I am making errors in mixing chemicals or developing my film or paper. Film is exposed by Fred using his standard set up. Paper is tested exactly as outlined by Mr., Davis. Despite carefully testing my paper and film I often seem to need a more "contrasty"(sic) paper to make the print that I desire, or that I consider to be satisfactory. Hence, I have started developing my negatives to a higher DR than would be indicated by my paper testing. For example, silver chloride grade 2 paper might have an ES of 150. For a better print I will reset the Plotter files used in ExpoDev for an ES of about 165-170.

I doubt that I am consistently using my incident meter incorrectly.

With variable contrast paper the issue is simple to solve, i.e., simply dial in more contrast. However, given the paucity of grades in paper with fixed grades, the issue becomes more puzzling. I see no other solution except as noted above-or arbitrarily adjusting the SBR so as to "creatively" drive development.

Has anyone found a similar issue?

I have spoken to others using the BTZS system who also find that negatives developed for VC paper ( grade 2 filters ) are too low in contrast. Consequently they have taken to developing their negativeds to a higher DR than would be indicated by their paper testing. They are careful workers who are diligent and attentive, and one has no reason to suspect that their testing is an issue. Happily, their solution is, as noted, rather easy.

I have read of Phil Davis's preference for negatives that are to the soft side. Was the Plotter written with such bias in mind?

I also believe that Mr.Davis stated that the BTZS system was meant simply as a "starting point" to allow one to more easily and quickly beomce proficient in the ability to make printable and reproducible negatives. If so, perhaps one should expect to make changes in development so as to fit one's vision and wishes. Mr. Davis stated as much, correct?

In addition, I gather that the Plotter program was written based upon Mr. Davis's testing with Delta 100 and D76. Such film was manufactured years ago, and might well have changed-along with modern emulsions that have evolved, but use the same name. IF indeed the emulsions have changed significantly, then might one wonder: Does the Plotter program have to be updated to reflect the contemporary Delta 100? If the assumption for base plus fog correct for modern Delta 100?

Fred-is step 21 exposed with black tape as Mr. Davis suggested in his articles? Is it necessary to use black tape when using the step wedge to test film?

I apoligze for the lenghty and rather complex post. However, many questions!

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Re: Negatives are often low in contrast 
Elliot  19:41 7 Dec 12 
Re: Negatives are often low in contrast 
Ben Wilbur  9:52 8 Dec 12 
Re: Negatives are often low in contrast 
Elliot  20:09 9 Dec 12 
Re: Negatives are often low in contrast 
David Jade  19:22 12 Dec 12 
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Philippe Bachelier  15:07 14 Oct 11 >> Forums home page Last Updated: 22 Aug 2002