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Is there a relationship between N numbers and SBR? 
Jorge Gasteazoro  10:52 3 Mar 03 
Re: Is there a relationship between N numbers and SBR? 
Phil  17:56 3 Mar 03 
Re: Is there a relationship between N numbers and SBR? 
Jorge Gasteazoro  18:29 3 Mar 03 
flash and the btz system 
howard schwartz  9:03 2 Mar 03 
Re: flash and the btz system 
Phil  11:51 2 Mar 03 
Howard --

1 - Why would you want to increase the exposure? It's been taken care of by the low reading; increasing it will simply add extra overall density without affecting contrast appreciably. Practically, of course, a 1/3-stop increase is trivial, so do it if you want to.

2 - You probably can't make the background completely white (devoid of tone in the print) with continuous-tone materials without distorting the rest of the gray scale severely. Well, that isn't quite true; you could blast it with a heavy-duty flash (if you have one) to raise its illumination level several stops above normal.

But the more practical step is to lower the high reading and settle for "white" instead of "total absence of tonality."

Remember that the incident meter will render a white area (or card) borderline white if you take the high reading in that same light condition. If you move the meter (and a white card) into a less bright area the meter will attempt to keep the card near-white, and that will make the background even whiter which is apparently what you want to do. You can check this effect visually in flood or modeling light but not with flash.

Again, the low incident reading establishes the initial film exposure; the highlight reading establishes the SBR; the SBR determines both the EFS (which may modify the exposure) and the development time (which controls overall contrast). To increase image contrast without affecting the exposure seriously, simply lower the high reading. That shortens the SBR and increases development.

-- Phil
 
BTZS Lite? Help! 
Phil  12:17 27 Feb 03 
Re: BTZS Lite? Help! 
Jorge Gasteazoro  20:49 27 Feb 03 
Re: BTZS Lite? Help! 
Phil  13:41 28 Feb 03 
Re: BTZS Lite? Help! 
Jorge Gasteazoro  15:16 1 Mar 03 
Re: BTZS Lite? Help! 
Robert S. Sfeir  13:55 30 Nov 03 


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