Increase the sensitivity of RC paper

Any ideas on how to increase the RC paper sensitivity before exposure? Any chemical baths? Weird stuff?

- Thanks

Welcome !


Basically the same as with film.

At least I do not see a reason why it should be different. And with film such was no success story...

Preflash I guess

HI Lexfilm Lab

Search for information in about "hypering" film. it involves bathing the film in warm hydrogen peroxide fumes to increase the relative ISO. I've never done it who knows, it might be able to be done with paper.

What exactly do you mean by increasing the paper sensitivity? If by that you mean you have a hard time bringing out highlight details, then, I agree with @NB23 that pre-flashing is the way to go.

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Pre-flashig paper does the opposite, it decreases the paper's sensitivity by fogging some of the contrast out of the paper, just like it does with chrome and c41 film, it it doesn’t increase and has nothing to do with its relative speed (ISO) paper has a speed that slides somewhere around iso 6 to around iso 24 depending on the quality of light . increasing sensitivity typically means increasing the top end of the iso from 24 to something higher, not fogging the paper so the user doesn't blow out highlights. OP if you are shooting paper negatives, instead of fogging / pre flashing the paper you might consider shooting through a enlarger filter (yellow) to tame the highlights, if you are shooting graded paper, use grade 1 ( with either of these methods, you iso will be in the tank ), or shoot on overcast days "sunny 11"and guesstimate your ISO as 6. Galaxy Photo ( who marketed the photographer's field book and direct positive chemistry kits ) had a paper that was almost as fast as plus x film ( about iso 100 ).. it was alleged to be Slavic paper stock used for photo booths .. they had slavic photo engineers working with them ...

Lexfilm Lab said:

Any ideas on how to increase the RC paper sensitivity before exposure? Any chemical baths? Weird stuff?

- Thanks

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I think it might be fair to say that collectively we none of us have been able to work out quite what the end objective is in trying to increase the sensitivity of RC paper

Maybe if you were to tell us this we might be able to help more?

pentaxuser

Preflashing, when done carefully, gives the paper an overall level of exposure such that any added exposure will develop out visibly (but properly preflashed paper would not develop to any visible degree). It does nothing to the actual sensitivity of the paper - it gives exposure of the paper a "head start". So, when you have a negative with dense highlights, you may more easily get detail in those areas in the print.

You can increase the speed of a paper emulsion with mercury vapour. I wouldn't, but some people would.

Don Heisz said:

Preflashing, when done carefully, gives the paper an overall level of exposure such that any added exposure will develop out visibly (but properly preflashed paper would not develop to any visible degree). It does nothing to the actual sensitivity of the paper - it gives exposure of the paper a "head start". So, when you have a negative with dense highlights, you may more easily get detail in those areas in the print.

You can increase the speed of a paper emulsion with mercury vapour. I wouldn't, but some people would.

Click to expand...

Technically speaking, you are of course correct, because preflashing won't alter the chemical composition of the emulsion and so won't affect the actual speed. However, when done properly (i.e., not heavy fogging), preflashing helps shooters to get more shadow details with negative films and printers to get more highlight details with negative printing paper. IOW, in practice, from ths POV, preflashing slightly increase the effective speed.

But, having said all that, I suspect that the OP doesn't really mean to ask about increasing the paper speed. In real world printing, the only scenario I can think of in which a printer may think to him/herself, "Mmm, I wish this paper has a higher sensitivity" is when the printer has a hard time getting enough density on a print. The classic example of that is of course the case of dense hightlight areas. This is my guess and thus the suggestion of preflashing the paper.

“increasing speed” is a broad term.

Pre-flashing does increase speed in a sense. It gives a boost.
And no, it does not make the iso value higher, therefore it does not enhance speed in the strict sense.

Mercury vapor? Who in the world wants to be exposed to that LOL

here are 2 threads from eons ago that mention hyper sensitizing film, I don't think anyone tried it on paper
it requires a mix of 8% hydrogen peroxide gas and 92% nitrogen gas..

it looks like someone did it with X-ray films ( similar to photo paper ) but it seems a bit different, you might need precautions