PDA

View Full Version : Fog on Old Tri-X Film



Luis-F-S
3-Feb-2014, 22:20
I have a lot of 4x5 Tri-X which expired in 1988 that I'm trying to use. The film was bought new and has been frozen the entire time except for 2 weeks following Katrina when we had no power. In my development tests, the film base density plus fog reads around 0.40, when I develop it for a Zone VII density of 1.14. The fb + fog does not change much regardless of the development time. Zone I is around 0.04 instead of 0.1, so most of it is in the fog. I'm developing it in one gallon tanks using HC-110 at a dilution of 2.5 OZ to a Gal for around 7 min at 70 Deg. I'm using an ASA of 160. If anyone has any suggestions on how to decrease the fog in the film either with different developers or additives, I'd welcome them. Thanks, Luis

Mark Woods
3-Feb-2014, 22:59
Rate the film lower for a denser neg. When you print, you can print down the whole image and still get good blacks since you'll have the range -- relatively speaking -- of a normal emulsion. You can still get the contrast, but it won't be the "normal" ASA. Do you know what zone 1.14 is? If you do you can compensate to place it at the bottom of a new range.

Hope this helps.

jcoldslabs
3-Feb-2014, 22:59
Luis,

You say that base fog does not worsen with longer development times, but have you tried very short times for comparison? 2.5oz of HC-110 into one gallon is a dilution ratio of roughly 1:50. I have successfully developed all kinds of long expired film, much of it much older than 1988, in HC-110 diluted 1:31 or 1:19 for anywhere from four to six minutes. I usually keep the developer on the cooler side, around 60-62F. My methods may not stand up to scientific scrutiny since I do not have a densitometer, but I have been happy with the results. Best of luck.

Jonathan


EDIT: What Mark says is also key. I rate most of my old films much, much lower than box speed, usually around EI 12-25. This pushes all of the values up off the toe and out of the fog.

Luis-F-S
3-Feb-2014, 23:32
Thanks, I'll try Dilution B; 1:31 with a shorter development time and 68 deg development. I do have a densitometer, so the film densities are accurate. I usually shy away from developing times of less than 6 minutes due to uneven development. I was rating the 320 TXP at 160. I'll try down to 100 or so and see if that helps. L

Leigh
4-Feb-2014, 12:15
The standard anti-foggant is benzotriazole. Should be lots of info on the net.

B&H stocks the Photographers' Formulary product.
http://www.bhphotovideo.com/c/search?Ntt=benzotriazole&N=0&InitialSearch=yes

- Leigh

Jim Noel
4-Feb-2014, 13:19
an addition of sodium Benzotriazole or of a 10% solution of potassium bromide to the developer will help. Your long development times may be adding chemical fog to the age fog.

Mark Woods
4-Feb-2014, 13:35
I'd read Dmin (base+fog) and look at a wedge, or good neg of yours, and base your exposure on the "new" Dmin on your out date film.

Luis-F-S
4-Feb-2014, 19:22
Yup, it's just that Zone I is typically determined by exposure, not development, so I assume the base fog will also not be too affected by development. That's pretty much what I've found. If I have to crank the ASA down to below 100 or so, then the film is so slow it's hard for practical use. Anyhow, I'll run some new tests next week around ASA 100-125 to see what gives. I'm out of town this weekend in NY and then off to Denver so the next week is pretty full. In the meantime I'll order some sodium benzotriazole from Photog Formulary and give it a try. L