Dark Circle on One Neg

I know the answer, but I wanna ask it anyway. Processed two rolls of Neopan in HC110 Dil 'B' yesterday afternoon. First time I have had this happen. On only one negative frame on one roll the negative has a small round area that is higher in density than it should be. Actually a larger round spot and then a smaller round spot next to and adjoining it.

Air bubble not dislodged during developing?

Confirm please. Just curious but sure.

Higher density would be increased exposure or development. An air bubble would make for lower densities. Perhaps a splash of developer hit the film? A bit of stray light? Are the edges of the denser area sharp, or is there a soft gradation at the edge?

C

No and I don't have a scanner. In the upper left portion of the frame, off the edge of the negative. ABout 3 mm from left edge. About 2mm from upper edge. Larger circle is about 3mm in diameter and the smaller circle is located at about o'clock from the larger one an is about 2mm in diameter. Slightly darker/ more dense than the immediate area of the negative. Not glare. I remember the subject. Wood fence. Edge of the denser area appears to be sharp. I presoak for one minute in Processing temp water. Could there have been an air bubble in this stage that allowed the developer additional action on this portion of the film surface?

That would probably do it.

I presoak for one minute in Processing temp water. Could there have been an air bubble in this stage that allowed the developer additional action on this portion of the film surface

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I do not see how this would make a more dense area; but what do I know?

Are you suggesting that an air bubble during pre-soak would inhibit water from pre-soaking the emulsion so that developer action began in that spot almost immediately upon introduction; that is, before the developer had a chance to displace the water in the emulsion where the emulsion had pre-soaked?

Christopher Walrath said:

I presoak for one minute in Processing temp water. Could there have been an air bubble in this stage that allowed the developer additional action on this portion of the film surface?

Click to expand...

Yeah, John. We're on the same page and I think we nailed it on the head. I agitate twice initially and therein laid the problem, me thinks.

It sounds like an airbell of the kind I got until I started giving an initial agitation of 30 seconds rather than 10 seconds. Pre-soaking didn't seem to make a difference.

But since there is more density not less, there was TOO MUCH developing. And since I presoak, there must have been an air bubble during the presoak that prevented the emulsion from soaking in water and allowed the developer to work unevenly in addition to the normal developing the bulk of the surface of the emulsion received.

Christopher Walrath said:

But since there is more density not less, there was TOO MUCH developing. And since I presoak, there must have been an air bubble during the presoak that prevented the emulsion from soaking in water and allowed the developer to work unevenly in addition to the normal developing the bulk of the surface of the emulsion received.

Click to expand...

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Adding an essentially unnecessary step like a pre-saok has added one more place for a problem. I guess, in addition to more agitation, one might consider a drop or two of LFN wetting agent in the pre-soak. Or, just eliminate the pre-soak. For myself, I never saw the reason for pre-soak; but then, what do I know? If you think your times are too short with HC110b, then just consider a weaker dilution with increased time.

Thank you, John. And everybody. I do appreciate the advice, as always. YOU GUYS ROCK!