Reciprocity effect and Delta 400

[sqphoto]

I use Delta 400, 120 film and I am interested in try to make exposures around 5 to 15 minutes. Has anyone had any experiences with this and if so what was your increased exposure compensation and or change in development. I read Ansel's info in The Negative but he only goes up to 100 seconds.

 

[MikeK]

Sandy King published film factors for reciprocity failure a while back for a number of films. I took that data and published chart and excel spreadsheet tables for a number of films. The metered times go to 1,000 seconds. I did not publish the times for Delta 400 but you should be able to get pretty close. You can find the chart and tables at

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Hope this helps

Mike

 

[sqphoto]

Thanks. Michael