Random white spots throughout negative

[yelmarb]

So these spots are most visible in featureless mid grey areas. Images were shot in the middle of the day, they're not stars.

My process is in a Jobo CPP2 processor with constant agitation.
D76 mixed with water at 55C and gently stirred until the water is clear.

Straight D76 @18C (process time was 7:30s)
1 min of Indicator stop bath
5 mins of Hypam Rapid Fixer
3 rinses at 30s each in the Jobo processor / drum
5 mins of wash with the Jobo Cascade
1 min final rinse with a 1:200 mix of Photof-flo and de-minearlised water.
Film is squeeged and left to air dry in a dust free room

I've since tried re-fixing them for another 5 mins with fresh fixer, along with another wash/rinse but the spots were istill in the identical places afterwards.

If there is an issue with the chemistry, then why are these spots appearing in a constant agitation process?

 

[koraks]

Was this 120 film or another format? This kind of issue is sometimes associated with the backing paper on 120 film, often exacerbated by storage conditions of the film.

A second possibility is incomplete dissolution of the developer (despite that it looked clear to the naked eye). Let it sit for 24 hours or so after mixing.

Finally, please don't squeegee your film. However, it's not the cause of your present problem.

 

[yelmarb]

Yes, it is 120 film that had been stored for a few years. Not sure how it was stored though.

Brand new D76 was mixed as recommended by Kodak on the packet. Powder was poured slowly into 55C water and stirred slowly until completely dissolved.

These rolls of film were developed a few days after the developer was mixed. It looked crystal clear in the measuring cylinder...

 

[koraks]

Then I put my money on an interaction between backing paper and emulsion. Give it a try with some fresh film and see if the problem goes away.

 

[Sirius Glass]

I suspect that the developer and other chemicals were not completely mixed.

 

[Dusty Negative]

Reticulation from temperature changes? I had a not too dissimilar result, also only in the midtones, with a roll of Tri-X a few months ago that I am moderately certain was caused by a temperature fluctuation between stop and fix.

 

[yelmarb]

I suspect that the developer and other chemicals were not completely mixed.

Supposing it wan't mixed properly, which I don't think was the case, how would I get these little marks in a constant agitation process?

D76 was poured in slowly to 55C water (checked with a ISO certified calibrated thermometer) and stirred with this mixing paddle for about 5 minutes until the solution was crystal clear. It was decantered into another 5 litre bottle where the 55C developer was allowed to cool and used 2 days afterwards.

How would you suggest D76 powder to be mixed?

 

[yelmarb]

Reticulation from temperature changes? I had a not too dissimilar result, also only in the midtones, with a roll of Tri-X a few months ago that I am moderately certain was caused by a temperature fluctuation between stop and fix.

All the chemistry and wash water was at room temperature (18C) when the film was processed. The benefit of using a Jobo processor is that it keeps the chemistry at a constant temperature.

Reticulation has a dark pattern to it.

 

[Grampadoug]

Interesting, I experience the same issue, with different chemistry. Using fresh (well within expiration date) 120 FP4 with Pyrocat HD (liquid), semi-stand. All chemistry is at room temp, 70*F, except my final rinse is with tap water, right out of the faucet which might be a little cooler (I live in a warm climate). What kind of film is the OP using?
Backing paper?

 

[yelmarb]

Interesting, I experience the same issue, with different chemistry. Using fresh (well within expiration date) 120 FP4 with Pyrocat HD (liquid), semi-stand. All chemistry is at room temp, 70*F, except my final rinse is with tap water, right out of the faucet which might be a little cooler (I live in a warm climate). What kind of film is the OP using?
Backing paper?

It's Ilford HP5. Probably the same backing paper....

I developed some Ilford HP5 4x5 in the same batch of chemistry, in the same way and there were no white spots in the mid grey arears..