"Black Hole" on negative

[Tadge Dryja]

Hi,

Today I tried tray developing more than one sheet at a time, shuffling the negatives. Since it's the first time I've done it, I'm guessing that development is somehow the problem.

So the negatives, on the whole, look good and evenly developed. I just made contact sheets, and noticed on one of them a black hole... it looks slmost exactly like a light source, except in reverse. On the negative, it's a small clear area. It doesn't have any defined edge, but gradually fades back to the surrounding image. It's maybe 3-4mm large on the negative / contact.

Has this happened to anyone else? What did I do wrong? If it matters, I'm using 4x5 HP5+, HC-110 dilution "H" for about 12 minutes. I processed 8 sheets and only one of them had a problem.

Thanks!

[MIke Sherck]

What are you using for stop bath? If you have an alkaline developer and an acidic stop bath which is too strong, it is possible (although I haven't heard of it in recent years) that the change from strongly alkaline to strongly acidic can (literally) "blow holes" in the film emulsion. Still, if this were the case I'd expect that you'd find more than one incident from several films processed together. Emulsion defect? Or possibly you made an unusual scratch during shuffling. I suppose that a fingernail could make a gouge in wet emulsion: they certainly can make linear scratches.

Mike

[Gem Singer]

Since the problem only appears on one of the negatives, it probably is not a chemically produced processing error. I would suspect a piece of material (dirt,flake of film,etc.) entered the inside of the film holder and adheared to the sheet of film when it was being loaded into the holder. It could also be caused by scratching the emulsion while it is wet and soft in the developer tray, either with the corner of another sheet of film, or with a fingernail.

[Ed O'Grady]

Tadge, it sounds like an air bubble attatched to the emulsion during processing, we used to call these air bells, without enough agitation this can happen. The density surrounding the clear hole will vary as the bubble slides around and finally breaks. Not positive this is what happened to you but I have seen it before.

[Tadge Dryja]

Hi

I used water as a stop bath, so I don't think it's that.

The air bubble sounds like the most likely problem. It seemed like I was shuffling a lot but maybe not enough. Thanks for your ideas. I think I might go back to developing one or two sheets at a time.

I'll probably print it anyway, it looks kindof cool, like this 'dark force' or something in the bushes :^)

[Donald Miller]

If you decide to print this negative and want to work at the elimination of the dark spot you may want to consider retouching the negative. A white spot on a print is much easier to resolve then a dark spot.