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Old 15th February 2009, 08:34 PM
Victor Krag Victor Krag is offline
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Join Date: Oct 2008
Location: Carmel, Monterey Peninsula, Ca
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Default HP5 Reciprocity Failure

I found a link to a reciprocity failure chart for HP5 while doing a Google search (http://www.flickr.com/photos/mikecostolo/435191155/). This gentleman used Ilford's datasheet to build a graphic chart. It appears from this info that HP5 needs an increase of exposure of only 12 to 15% beyond a 1 second exposure. This makes sense to me because my personal history had been getting over-exposed long exposure HP5 negatives too often until I pretty much said to myself "enough, I'm only going to give a couple extra seconds". I should note that I generally under dev in both agitation and time, too. I just checked out the 4x5 HP5 negs that I shot yesterday and processed last night. They look well exposed and devved. 1 sec exposure w/ yellow filter (spot metered @ 400 asa +1 filter stop) in Pyro HD 1:2:100 at 70F for 7.5 minutes. 1st 30 45 sec / 2 smooth inversons with 2 taps per min. I only wish I took more time to focus, it was miserable weather with intermittent sprinkles and LOTS of wind, dark cloth was blowing onto the GG.. ah well, it was fun.
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