little spots of less-density in negs, but not dust

[Jordan]

So I have these little spots of less density in some of 4x5 negs lately. They aren't completely clear clear like dust would be and have been happening in clear skies. Did I get an iffy batch box of Tri-X or is there some chemical process that could cause this. Could too strong a stop bath be the culprit or leaving it in a permawash too long cause something like this. I'd like to avoid it if possible. I thought maybe it was drying marks also, but am using distilled water and LFN. Anyhow, as always thanks in advance and you guys are the best!

[Bob Salomon]

Air bells?

[Jordan]

I use a jobo expert drum to process the film and it's being constantly agitated. It looks like what are air bells or bubbles would be, but where in the process would this happen?

[jeroldharter]

Are you doing a pre-wet prior to development?

[Bob Salomon]

I use a jobo expert drum to process the film and it's being constantly agitated. It looks like what are air bells or bubbles would be, but where in the process would this happen?

Usually where the chemistry forms drops on the emulsion that are not removed by agitation. With our Combi-Plan tank for 45 as well as most roll and 35mm tanks the instructions call for rapping the tank after filling with developer. This is to dislodge any air bells. If you are getting them on a rotary tank then the agitation may not be correct.

[Jordan]

I pre-soak for about 5 minutes, hc110 1:90 for 8 minutes, stop 3/4 strength for 1 minute, fixer at film strength for 5 minutes, permawash for 5 minutes, archival film washer for 30 minutes, distilled water and LFN.

[Jordan]

Agitation is 30 rotations per minute in one direction. With all chemistry being introduced to drum while spinning.

[Bob Salomon]

Agitation is 30 rotations per minute in one direction. With all chemistry being introduced to drum while spinning.

Try reversing direction during development.

[dsphotog]

I'd bet it's happening during development... Try reversing rotation manually after the first minute, then every two min.

[Jordan]

It never happened in the past with rotation in one direction, but will consider it. I mean is it possible to get a bad box of Tri-X?

[Jordan]

Ok how about air bells forming after a pre-soak because of introducing the developer a minute or so after dumping out the pre-soak water?

[Daniel Stone]

try a water stop,

I do 2 changes of water, 30s each

I tray develop b/w though, but for 4x5 I use a Jobo tank/reels, but I always had spot marks(like your said problem) when using an acidic stop bath. When I went to a water stop, no more spot marks :)

-Dan