Test procedure for even development?

[Jeff Bannow]

I would like to run a test of my 4x5 sheet film development process, specifically looking for evenness from agitation. Here's my plan:

1. Find an evenly lit wall in the sunshine and meter for middle gray. Take a picture.
2. Develop.
3. Examine and look for any anomalies on the light table.

This seems so simple, that I must be missing something. Anyone have a preferred method?

[Overkill-F2]

Are you tray developing your 4x5's?
I might expose three sheets, zone 3, 5 and 7, contact print, then examine them.
...Terry

[Jeff Bannow]

This will be inversion processing.

[wildbill]

Jobo, expert drum.

[albada]

I would like to run a test of my 4x5 sheet film development process, specifically looking for evenness from agitation. Here's my plan:
1. Find an evenly lit wall in the sunshine and meter for middle gray. Take a picture.
2. Develop.
3. Examine and look for any anomalies on the light table.
This seems so simple, that I must be missing something. Anyone have a preferred method?

Illumination of lenses tend to fall off near the edges and corners. Perhaps expose the film using the enlarger at f/16 instead? Or put the film on the counter and blink a light in the darkroom?
Also, the human visual system has a hard time seeing gradual changes in luminance. I suggest using a densitomer, or placing a light meter in various places on the film to measure densities.

Mark Overton

[Jeff Bannow]

Jobo, expert drum.

Sold my Jobo, Vinny.

[Michael R 1974]

Use your enlarger - assuming it illuminates evenly. Raise the head way up and stop down so there's no falloff. Expose a sheet of film to some mid-tone density. Process it. And then contact print it.

What kind of tank/system are you using for inversion?

[Jeff Bannow]

The best way to do it is use your enlarger - assuming it illuminates evenly. You raise the head way up and stop down so there's no falloff. Expose a sheet of film to some mid-tone density. Process it. And then contact print it.

Interesting - I've never exposed film via my enlarger before actually.

So:

Turn off safelight.
Get the enlarger head to a point with even illumination and stop down lens.
Use incident meter to make exposure in the multiple second range.

I assume I could just do all of this in a normal double-darkslide 4x5 holder.

[Michael R 1974]

Ideally I'd just put the sheet flat on a piece of black cardboard on the enlarger baseboard (to eliminate any chance of flare from the film holder along the edges of the film).

What kind of tank/system for inversion?

[Jeff Bannow]

What kind of tank/system for inversion?

Mod54 in a Patterson tank.