Modifications to Kodak 8x10 hangers for even development of double-sided X-Ray film

[Sam L]

I've been working on developing Fuji HR-U double-sided x-ray film in 1-gallon vertical tanks with Kodak 4A hangers and have made some good improvements that I wanted to share.

I created a repeatable test that accentuates uneven development issues: I put 4 sheets of 8x10 film into film holders and then flash them each with a dim bare bulb for 1/10s. The resulting negatives are even but over-exposed. I then develop them in 1:250 510-pyro in vertical tanks using inert gas agitation with the standard 1s on 10s off pattern until the negatives are quite dense. The dilute pyro is unkind to uneven agitation (surge marks) and to insufficient agitation (bromide drag).

Here's the starting point with unmodified hangers:


I then increase the "dehaze" setting to +50 in Lightroom to really bring out any unevenness:


As you can see, the side and bottom edges have surging issues from the developer moving through the holes in the hanger. The top shows four white marks due to the hanger's springs touching the back side of the top. Here's an unmodified Kodak hanger for reference:


I did a bunch of experiments and ended up with three modifications:
1. Close the holes in the face
2. Cut open the bottom of the hanger
3. Raise the clip at the top so that it only touches the margin of the photo and extend the face so that it still holds the photo in.

Here's the result:


The surge marks on the edges are gone. The clip marks on top are gone. The evenness in the center is imperfect but unchanged. There remains some ghosting at the edges where the film sits in the hangers.

I'll follow up with details for each modification.