What a drag!

[Sazerac]

It looks like I may be a victim of bromide drag. I can see some streaks in the sky of an image that I processed the other day. I am using the MOD54 processing tank and it looks like the streaks align with the ribs that hold the film in place. I have highlighted the areas on the attached image and have included a higher contrast version so that it is easier to see.

I have read that bromide drag can be caused by insufficient agitation and residual photo flo on the processor. I am shooting Tri-X and developing in HC-110 Dil. E to get the times above 5 min. I typically agitate using the swirl stick for the first 30 seconds and then for a few seconds each minute after that. I haven't worked up the courage to invert the tank because I fear that the film will get dislodged. I'll probably give the inversion method a try next time, but are there any other suggestions on how to develop using this developer and tank?

[Brian C. Miller]

That isn't from insufficient agitation. That's from agitation in only one direction. Take a look at the top, and you'll see the crimps where the MOD54 holds the film. You need a back-forth-back-forth-back-forth (twitchy) action to create a sufficiently randomly disturbed flow. Try a very gentle inversion method with the MOD54.

The Yankee tank also does something similar. The plastic hanger forces the wrong flow on the film, so there is always a development pattern matching the slots in the plastic.

[Kirk Gittings]

It could take you a number of trials to solve this. You don't need to test this on actual shots. The best exposed film to test agitation is something like of an evenly lit, out of focus wall, placed on middle grey. Any detail will tend to obscure problems.

[Sazerac]

Thanks for the responses! I'll give the inversions a try.

[Doremus Scudder]

Back when I was shooting 120 a lot I had a similar problem. I spent an entire afternoon and about 10 rolls of film just unrolling the film, stepping on the enlarger footswitch to expose evenly, loading a reel and developing with yet another agitation scheme.

I found, for my set up of stainless steel reels and tanks that I had to not fill the tank completely; just enough to cover the film, and that I really had to shake the hell out of it when agitating. That solve my problems.

Best,

Doremus