kodak B/W Print positive 7302 - ASA?

[Richard Tuohy]

G'day,

I want to try some experiments with using Kodak's BW print stock (7302) as a high contrast (and very slow!) camera stock. I have heard ASA ratings from 3 to 12. Actually, one thing I want to do is cross process the stock as a reversal which would efectively double the asa. Kodak don't seem to have the asa of this stock listed on their web site.

Anyone help?

Richard T.

[John Pytlak RIP]

G'day,

I want to try some experiments with using Kodak's BW print stock (7302) as a high contrast (and very slow!) camera stock.  I have heard ASA ratings from 3 to 12.  Actually, one thing I want to do is cross process the stock as a reversal which would efectively double the asa.  Kodak don't seem to have the asa of this stock listed on their web site.

Anyone help?

Richard T.

<{POST_SNAPBACK}>

 

Speed ratings (EI) are only applied to camera stocks.

 

Although Kodak publishes sensitometric data for all its motion picture films, it's hard to compare a blue-only sensitive stock like 7302 with a panchromatic camera stock. With a non-standard reversal process, you are on your own.

 

I'd suggest starting at EI 3, and run a wide exposure series to narrow down the speed for your conditions.

[Richard Tuohy]

Thanks for that John,

I see. I realised it was not panchromatic, but that explains why no asa! I will have to do tests.

R.P.T.

[Dominic Case]

I will have to do tests.

Oh yes, you certainly will. That's the joy of playing with non-standard stocks and processes.

 

With normal processing, B/W print stock has a gamma about 4 times that of B/W negative, and consequently, is very exposure-critical. Half a stop either way will make a massive difference to the image, as the stock can record a brightness range of only 3 or 4 stops (depending what gamma you process to).

 

If you want more than blue-only sensitivity, you might try panchromatic sound negative stock 2374. Beware - it's polyester based.