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Development Time


Stealth3kpl

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Does a longer development time increase or decrease contrast of the negative?

Pete

I assume we are discussing black & white negative film.

 

Technically, with most film (not one with a straight line density curve (no shoulder)) longer development adds density and lowers contrast, however we have to take it to extremes to see that case, and the negative might become unusable.

 

For our purposes, increasing development increases contrast as long as exposure is correct - that is when the distribution of the scene is nominal-normal - there are shadows, midtones and highlights. However, as development increases more, the middle tones will move closer to the highlights and therefore contrast will be reduced. Increasing development beyond that will fog the unexposed parts of the film which adds density everywhere, including shadows where detail will be obscured by fog so much that it may as well not exist.

 

Clear as mud?

 

Note that increasing negative density by over development can be so great that the image will require very long exposures in optical printing (contact or enlarger) and might be impossible to scan.

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If color or bw negative is overdeveloped it is darker and more dense. I have done it :) 

And then it is harder for scanner and I guess this is how it comes with more contrast. Under enlarger it makes it more difficult and with narrower choice of filters, papers. 

 

I do develop longer due to pushing of bw ISO 400 films. If film is right and I'm doing it right, then it comes with increased contrast. Well, on prints and slightly. But then, again, it limits me with filters and paper choice.

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General experience is that Tri-X in HC110 is best exposed for 200 ASA. Will give good shadow detail without blown highlights normally.

 

Start with your 5.75 min, and adjust development time to give good contrast prints using a grade 2.5 filter. 

 

Make prints - you can't properly judge to a useful level of accuracy by looking at negatives. 

Edited by Michael Hiles
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I'm going to scan so perhaps development time isn't so important?

Pete

 

I don't think so. It does matter.

 

Whether you print on paper or scan, you want the best negative you can get. In my experience for scanning, a slightly softer negative is better than a hard negative. (i.e. slight underdevelopment is preferable to overdevelopment - please note "slight"). Still - "ideal" is ldeal. You want as much information as possible from the negative to be picked up by your scanner. With an overdeveloped negative information in the highlights or deep shadows (or both) will be lost. To be avoided.

Edited by Michael Hiles
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The best way to learn is to make careful tests using your own gear. The key is to change only one variable at a time and keep others constant. This includes things like water temp and agitation method/time. Write everything down and create standard practices.

 

I used to make film speed and development time tests to establish normal base times, and then kept print 'recipe' pages for every negative/print combo (including dodging/ burning diagrams) so that all steps and conditions could be recreated for making future prints.

 

I agree with Michael that a good negative, that records all important tones, remains your best friend. Even for prints, contrast can be addressed via papers and other post-negative development actions.

 

Jeff

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I'm going to scan so perhaps development time isn't so important?

Pete

 

Not true.  Same a printing.   Some films will scan ok at the best time for printing.  Others require different.   Plus x would not scan and print optimally at same development time.  Unfortunately Kodak solved that problem for us.

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