Uneven Developement with Diafine - how to test properly?

[zechi]

Hi all,

I'm very new to self developing my 9x12cm black and white negatives (Fomapan 100) and am having trouble with uneven developement. I use Diafine, and a Paterson tank with the taco method, but I also got uneven developement when using trays.

I tried different agitation schemes from the box instructions to the method of "eye of wally" described here

eye of wally's method

.. always uneven development. It seems to me that the harder I agitate the better the negatives get - I ended up inverting for 30 seconds in A and B and after that 5 times every 30 seconds - almost continous agitation but still no even developement. My temps are fine and I used distilled water to mix the chemicals - I also use distilled water for the final rinse.

What would be the best method for testing or for working out a proper agitation scheme? Should I take some test shots of say, an evenly lit wall or is it possible to just take out a sheet of the film holder, expose it to daylight and develope the sheet? It should come out evenly dark shouldn't it? I find it hard to judge the developement of regular pictures sometimes, so I wanted to test in a more controlled manner.

Thanks in advance for your answers & all the best,

Christoph

[Mark Woods]

An evenly lit surface at about 18% will show off any problems you may have regarding development.

[Ken Lee]

You may find that development in a continuously moving motorized tank (at sufficient speed) eliminates the problem.

[Nathan Potter]

I'll second Kens' comment. I use a small motorized tank with just one sheet of 4X5 film with continuous agitation, then toss the developer after each sheet. Don't seem to have any unevenness problems with Diafine unless I've had too much wine and goof. Just used a 2 year old part A and part B solution. Hit the density scale perfectly (well < 0.05 error, at least) and no unevenness.

But I also use tank immersion development with multiple films and with old Kodak SS film hangers and continuous but gentle swinging agitation with no unevenness. I'm mostly calibrated for 3 min. A plus 3 min. B development times at 75 F.

Nate Potter, Austin TX.

[Leigh]

Hi Christoph, and welcome aboard.

You're WAY over-agitating. The instructions say:
"...agitate VERY GENTLY for the first 5 seconds, and for 5 seconds at 1 minute intervals."

Follow the instructions on the box. I don't know who authored the instructions you're using, but I guarantee it was not the manufacturer, so they're useless.

Diafine is a compensating developer. All compensating developers need to sit undisturbed for most of the time so they can work as designed.

Diafine is the most forgiving developer on the planet.
I've used it without any problem for over 50 years.

A couple of points:
NO pre-soak of any kind. Pour Solution A into a dry tank with dry film.
Leave each solution in for five minutes.
Processing temperature should be around 70°F, but it does not matter much, and time does not change.

- Leigh

[BetterSense]

With 35mm I found it important to follow the instructions. I agitate very gently maybe 1 or 2 agitations at the start, and again at 30 seconds. I don't agitate again after that because, well, it develops out fully in 3 minutes and mostly in 1-2 minutes anyway. If I agitated less than that I got marks from the sprocket holes; more and I got inconsistent huge grain.

I never used Diafine with sheet film.

[Leigh]

I should add that I use Diafine with all film sizes including 35mm, 120, 4x5, and 8x10.

- Leigh

[frotog]

Your uneven development could very well be due to the long pour times when introducing the b solution. Try turning off the lights, open your Patterson tank and pour the b solution in directly, mindful of limiting the amount of time that transpires before your first agitation in solution b.

[zechi]

Thanks for your quick answers!! Maybe I really did over - agitate ... I'll take some test shots tomorrow and try again with the box recommendations. Could the taco method I use also be a problem in combination with diafine?

As for a motorized tank - would something like a Paterson orbital work?

Also, thanks for the tip with minimizing the pouring time I'll give that a shot too!

thank you for your help,
Christoph

[zechi]

ok so, I finally found the time to take a test shot and develope the negative .. the result is very bad - I tried the box suggestions and agitated gently every minute for five seconds. I inverted the tank gently and tapped it on the counter after every agitation cycle. I did not presoak this time and rinsed the negative after B - I fixed for 5 minutes with constant agitation. I attached a quick scan of the negative. Sorry for the dust but at the moment thats my smallest problem ;-) ..The wall was illuminated by two 1000 watt lamps and appeared to be uniformly lit - my digital camera proved this ;-) ..



It's quite frustrating, not matter what I do, the result doesn't even change much - I always get these blotchy negatives. Nevertheless I would really like to work this out since I've seen very nice negatives developed in diafine but can't imagine what I'm doing wrong .. Maybe I should walk away from Diafine and try another developer - I would like to use a hybrid workflow, is there a developer which is particularily suited for scanning?

Thanks,
Christoph