large format printing - 4x5

darkroom_rookie

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Ian Grant said:
With B&W and some papers it can affect the contrast.

Ian
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Does it affect recent RA4 papers such as Ultra Endura? Does the contrast increase or decrease with long exposures? Can the contrast be successfully reduced by adding sodium sulfite to the developer? (A lot of questions, I know...)

d_rookie
 

RalphLambrecht

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darkroom_rookie said:
Does it affect recent RA4 papers such as Ultra Endura? Does the contrast increase or decrease with long exposures? Can the contrast be successfully reduced by adding sodium sulfite to the developer? (A lot of questions, I know...)

d_rookie
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My measurements show a slight contrast increase with exposure time, probably due to an elevated exposure loss in the shadows, causes by non-uniform reciprocity failure.
 

BetterSense

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I wouldn't know; was under the impression that the only way to control contrast with color negative printing was to use a different paper or film, and there aren't many papers available anymore.
 

Ian Grant

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The effects of long exposures on contrast can also be affected by scattered reflections causing fogging, not enough to necessarily raise base fogging rather having a similar effect to flashing. Most enlargers spill some light and this is why black walls are usual near enlargers, but columns often have chrome plated parts and I've seen issues on odd occasions.

With RA-4 Colour balance can shift slightly with reciprocity, this is why pro labs calibrated their roll head printers so the exposures were constant regardless which lens (so enlargement size) was used.

Ian
 
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RalphLambrecht

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BetterSense said:
I wouldn't know; was under the impression that the only way to control contrast with color negative printing was to use a different paper or film, and there aren't many papers available anymore.
Click to expand...

As Ian(?) said: different developer work.
 
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