Anyway to boost the sensitivity of RA4 paper ?

[rbrigham]

Hi All

I'm making RA4 reversals in camera and was wondering if there was anyway to increase the sensitivity
of the RA4 paper even if it reduced the image quality elsewhere

presently I get about 12 ASA
50 would be great 100 would be amazing ...

best

robin

 

[koraks]

You could try preflashing to lift the shadows a bit, giving you effectively a tad more speed and reduced contrast.but getting up to 50 is probably not going to be possible in any scenario.

 

[rbrigham]

You could try preflashing to lift the shadows a bit, giving you effectively a tad more speed and reduced contrast.but getting up to 50 is probably not going to be possible in any scenario.

thanks Kodak's i'll give that a go

best

robin

 

[Donald Qualls]

Another option would be to change the B&W developer you use for first developer -- use a phenidone based film developer (at stronger than normal concentration, if you would normally dilute -- just as Dektol is usually 1+1 or 1+2 for paper vs. 1+9 for film) and you'll pick up half a stop or so in real speed, which will translate directly to the color reversal. This can be combined with preflashing (test the developer first, then the combination of developer and preflash). Preflash will reduce overall contrast (pulls up shadows with little effect on midtones and highlights), while a speed-gaining first developer will raise everything together.

Another possible option (which I have used with B&W reversal) is to add some (more) fixer to the first developer. This will reduce the amount of halide remaining to be exposed and developed in the color developer, so lightening the final result. In my experience, adding a pretty small quantity of thiousulfate to the first developer allowed Tri-X to be reversed at up to EI 800 with excellent detail from shadows to highlights. You would surely need to test the effect of this for your RA-4 reversal, since it's hard to predict (but easy enough to test).

 

[rbrigham]

Thanks Donald
lots of things to try

best

robin

 

[Jimskelton]

Try rinsing the dye layer off of the paper before shooting the negative. This should add around 2 stops since you'll be using less filtration (around a stop), and the paper won't have a cyan filter (another stop) in front of it (Fuji Crystal archive).

I found when you rinse the dye layer off, the paper is balanced to around 3200K, but may need a bit more yellow/magenta.

I found rinsed paper without filtration shoots around ISO 12.

 

[xkaes]

For pre-flashing, make a step-table on a 10" strip of paper with exposures of, for example, 1s, 2s, 4s, 8s, 15, 30s, 60s -- without a negative, of course.

Then find the first step with ANY density -- for example, 8s.

Then fine tune it, for example -- 4s, 5, 6s, 7s, 8s.

When you find the LAST step with NO density -- use that as a pre-flash time.