pre-flashing paper negs

Light, film, exposure..
Ray Heath
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Joined: 15 Oct 2012, 13:21
Location: Lower Hunter Valley, NSW

pre-flashing paper negs

Postby Ray Heath » 07 Dec 2012, 17:59

Comments in another thread have prompted me to do some RC VC paper neg testing.

I'm aware of 3 methods to reduce contrast in paper negs, pre-flashing, use of yellow taking filter and processing in half strength paper developer. Should I use just one of these techniques, a combination of two or all three together?

This afternoon I've tried various combinations of these techniques and by eye it seems my best result was;
pre-flashing with MG 3 filter,
exposing at ISO 3 in bright overcast,
and processing in half strength MG dev.

i.e. I've used all three techniques together which produced a soft neg with a range of tones that scanned really well and could be adjusted easily in PS and will I assume print easily by contact.

RCTestNeg-AsScanned.jpg (49.96 KiB) Viewed 1312 times

RCTestNeg-Flipped&Inverted.jpg (50.5 KiB) Viewed 1312 times

RCTestNeg-LevelsAdjusted.jpg (56.78 KiB) Viewed 1312 times

What methods do you guys use?

Frank Meadow Sutcliffe's photographs are "a bridge that spans the widening gulf of time" (Michael Hiley 1979, 5).

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Joined: 27 Jul 2012, 16:02
Location: Noosa

Re: pre-flashing paper negs

Postby Maris » 13 Dec 2012, 16:37

The principle contrast modification technique I try for variable contrast paper negatives is yellow filtration.

The yellow filter exposes the low contrast grains in the variable contrast emulsion mix. A dark yellow filter, almost orange, has the strongest effect but at the cost of light sensitivity because the filter acts like a safelight. A red filter is effectively opaque since red light doesn't expose paper.

Yellow filtration also reduces the overt blue sensitivity of photographic paper and does contribute to nicer skin tones...but not enough, I reckon.

A contrary effect is the tendency of a yellow filter to darken shadows in daylight subjects. The shadows are filled with blue light so the filter holds them back and excessive contrast reappears.

Frankly I've never solved the paper negative "problem" and my excuse for giving up the chase is that photographic paper doesn't have enough silver in it. The silver on paper holds back light on the way in and then holds back the reflection off the paper base. So a given amount of silver on paper works twice as hard as the same amount silver on film. Photo paper manufacturers full well know this and put way less silver on paper than film. The result is that photographic paper used as a contact or projection negative has a disappointing reduced dynamic range of densities compared to film.

I suppose a paper negative can be scanned as a reflective object and and the acquired electronic file can be reprocessed so that it will display as a positive on a monitor screen. But personally speaking, in the context of actual photograph making, that is too paltry a result for me to bother with.

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