Reciprocity Failure of Ilford HP5 Plusgreenspun.com : LUSENET : Large format photography : One Thread
Hi, I requested from ILFORD a chart to help with reciprocity failure of ILFORD HP5 Plus sheet film. I got the chart in no time but the longest exposure time was something like 35 seconds. And there it ends. Can anyone who uses Ilford HP5 Plus sheetfilm give me some advice how to properly compensate reciprocity failure when the lightmeter reading is 1, 2, 5, 10 minutes? I have recently started to use my TOYO 4x5 and 8x10 as pinhole cams, so exposeures readings of 5-10 minutes is quite common.
-- Erich C. Decker (firstname.lastname@example.org), August 21, 2000
Hi Erich, how are you developing this film with these long exposures? David
-- david clark (email@example.com), August 21, 2000.
From a table on side of my meter, here are my times for HP5 which I develop in pyro: indicated: 30" 1' 2' 4' use: 2'25" 6'20" 28' 2hrs 10' develop: -14% -18% -24% -30%
Hope this helps (and stays lined up so you can decifer it.
-- John Hennessy (firstname.lastname@example.org), August 22, 2000.
1' - 7'37", 2' - 16'14", 5' - 53'18", 10' - 132'. Also note that a development decrease of an average 30% is recommended.
I have no idea where I got the chart those times came from or if they're valid.
-- John Hicks (email@example.com), August 23, 2000.