Change of density at film hanging clips on dip-dunk processing

[Neal Chaves]

I suggest that the increased density of the negative in those areas is due to the compression of the clips on the emulsion.

[schafphoto]

I suggest that the increased density of the negative in those areas is due to the compression of the clips on the emulsion.

Perhaps, but compression seems unlikely since after decades of similar clips being used on Refrema and Sitte-Tischer racks, I would think it would have been engineered out of the system by now if compression, kinking or impact damage was the cause. I'd ask you how does clip compression effect film density exactly?

[schafphoto]

Attachment 233255
I commented on this the other day and just came across this today in a 1973 Kodak technical publicationAttachment 233256
The images are upright on my computer!

Thanks ASA1000.

For future readers of this thread, the Kodak publication mentioned and excerpted by ASA1000 is available as a complete PDF in a few places on the web in December 2022.
Try searching "Kodak J-1 Processing chemicals and formulas for black and white photography" and you should find links to PDF's of the entire publication.

[Neal Chaves]

Increased density in the area of a clip would depend on the emulsion type. Some may allow more spread through the emulsion than others just as some film types are more prone to “light piping” through the film base than others.