Uneven development

Hi,

 

I am getting uneven development from my 120 roll films that I never

got before. What I'm talking about is that the first 6 frames are

noticeably darker than the last 6, as if they had gotten more

devlopment or less fix.

 

I never had that problem before and I have been developing film for

over a year now. This happened to me with T-Max dev. and D-76, so I'm

almost positive that it is not a question of developer, although, my

D-76 is a few months old, so it might be time to change.

 

I have thought that the plastic Paterson reels might be the problem,

but then again, i don't understand why this did not happen before.

 

Unfortunately I cannot post any samples, but just try to imagine half

the roll darker that the other half.

 

Thanks for all your responses.

 

Regards,

 

Radu D.

Since I have done a great deal of testing, I h ave only seen this with radical agitation techniques.

 

Patterson tanks, use the "spinner". 2 turns to the right and two to theleft repeatedly for the first 15 seconds.

 

Thereafter, two turns to the right followed by two turns to the left and let it alone for the next agitation cycle.

 

For high resolution, agitate each 30 seconds.

For medium speed and 400 speed films, agitate each 60 seconds.

For increased edge effect, agitate each 2 to 3 minutes.

 

If you spin a lot in th esme direction to the side where the developer is scooped in it may do what you are seeing, that is why you always reverse the twist each time.

 

In a Patterson tank, developing as I suggested, a fogged exposure of 1.00 should be 1.00 +/- .04 or 1/7th of an f stop. That is several orders of magnitude better than most commercial labs.

 

Lynn

Thanks Lynn,

 

I hadn't thought about this, but I think you're right, I always turn the same way, although i don't use the spinner.

 

I'll try your technique, thanks a lot.

 

Regards,

 

Radu D.

I'm sure Lynn's technique works for her. It sounds a lot like the agitation scheme I use with good results as well, though I tend to agitate a bit more vigorously. With my plastic Patterson look alike tanks I agitate continuously for the first 30 seconds using a back and forth motion. For the remaining time I agitate for 5 seconds every 30 seconds, going through about 6 back and forth motions in each 5 second agitation interval. I've found that vigorous agitation for the recommended interval, followed by the appropriate rest interval, works out best. At best, it insures that all the developer at the film's surface is exchanged. At worst it makes no difference compared to a technique that uses more gentle agitation for the same intervals.

I use Paterson tanks and have done for twenty-odd years. I use inversion agitation: four inversions in the first 30 seconds then one inversion every 30 seconds thereafter.

Lynn is an old master, but I can appreciate how you may not get the same fine results he does. I tried to duplicate a technique taught to me by a wedding photographer who agitated only twice in seven minutes development of plus x and d 76. I got absolute disasterous results with hugh streak marks. I followed the exact timing, lift height, and rotation of lift rod he advised.

 

The Patterson tank instructions call for using the twist rod only for the initial agaitation after the developer is poured in. The cap is added during the first rest period and then inversion is used at two inversions per cycle. The cycle may be a long or short as you want. I adopted this on the first roll and never had a problem.

To Frank Schifano,

 

This her is a he, a 74 year old pro photographer guy of 57 years experience and a professor for 16 years.

 

Just thought you'd like to know. I've done processing research and quality control for many years and always try to make photographers work better with the tools they have access to.

 

Best regards,

 

Lynn