Those of you who run test-strips may find this holder useful. Anyone can make it, and it closely mimics the environment of a roll of film. In particular, it eliminates the problem of developer-currents causing uneven (or extra) development in the strips.
Using a hacksaw, I cut a PVC pipe fitting in half, and cut two interior slots in which the strip slides.
When in the tank, the emulsion faces down, so there's a narrow space between emulsion and tank-bottom, similar to the small gap between layers on a reel. As a result, the strip develops similarly to a roll. The crosspiece that's epoxied to the top prevents this strip-holder from turning upside-down during agitation.
I exposed a 21-step Stouffer wedge twice, first with low exposure to show the toe, and again with high exposure to show the shoulder. The bump at X=3.0 is where the two graphs were stitched together.
You might have noticed in the first photo that there are two frames on the strip. On the roll, I made low/high exposures in alternation, so each test-strip has both, showing everything the developer is doing, from toe to shoulder.
This device is an improvement over the baffles I've been using. Comments, questions or suggestions?
EDIT: I'm using a one-reel tank. It's so short that, with the crosspiece, there's not enough vertical space for the PVC strip-holder to turn upside-down, so agitation by inversion works well.
Last edited by albada; 11-15-2012 at 05:00 PM. Click to view previous post history.