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Old 24th March 2010, 03:20 PM
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Default Film agitation?

OK! This is an area I thought I had a good handle on but the more I considered the effect of agitation on development the more I have bewildered myself.

I've been using 120 Delta 3200 @3200 for shop interior shots without flash and I have considered the results have far too much grain. Developed in DDX for 9.5min @20C and agitated for 15sec every minute. Today I reshot an interior on D3200 @1600 and developed in DDX @20C. This time (having researched a little) I agitated for 15sec for the first 2min and then 5sec every other min. To compensate for the less agitation I developed for a total of 10mins.

The result was a negative with very good contrast and much less noticable grain.

I always thought agitation had to do with keeping fresh solution in contact with the film surface for even development. If so why does less agitition produce a better negative? Also what bearing does it have on grain size? My research never gave me this answer!

I know this is probably a no brainer and I have possibly over analysed the matter but can you point me towards some clarity!

Paul
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Old 25th March 2010, 05:55 PM
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Hi Paul,

Grain in any film is increased by over agitation and over development as well as an increase in temperature which causes over development if you get the time wrong. Delta 3200 clearly is a quite grainy film when exposed at 3200 or over, many say that its true speed is somewhere between 800 and 1200 ISO. I'd suggest that the results you produced from the first film exposed at 3200 were about normal. The second film rated 1600 and developed using the partial stand development you describe was always going to produce less grain for the reasons I gave in my opening sentence.

You are correct in thinking that agitation is required to refresh the developer on the surface of the film but the change in agitation you used for the second film was relatively little and the overall development time was not huge, partial stand development also works in helping improve edge development, known as acutance, which helps increase contrast as you discovered. You may be interested to know that I develop most of my film using the partial stand method as do many other photographers.

I hope this answers your question.
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Old 25th March 2010, 10:07 PM
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Cheers Les. This partial stand method is not a technique I have used before but obviously worth more experimentation.
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