Receprocity characteristics of Efke 25?

[Mike Tobias]

I've searched a number of different places to see if I could find any info on this, but as of yet have been unsucessful. I was wondering if anyone has any experience with the reciprocity charateristics of Efke 25 film. Most of the photo's I'm going to be taking are going to be in fairly subdued light, and as I only have barrel lenses that I stop down, the exposures are going to range from a few seconds to minutes. Does this film stay fairly consistant in exposure times < 1 minute? If anyone has any, or knows where to get them, I'd love to have compensation times as well. Thanks in advance for all your help.

Mike

[Scott Killian]

I've shot quite a bit of Efke 25 with most of the exposures in the 1" - 2 minute range. I used the same reciprocity times I've seen for some other films like J&C 200 and it's worked fine for me in both ABC Pyro & Pyrocat. Watch for scratches - Efke films have very soft emulsions. Try:

Meter / Exposure Given (All times in seconds)

1 / 2

2 / 5

4 / 15

8 / 35

10 / 50

20 / 120

30 / 195

40 / 300

50 / 405

60 / 525

70 / 600

80 / 825

90 / 1005

100 / 1200

[Tim Curry]

Mike,

I've looked for this data and as yet haven't found it in published form. I was told that I would start noticing a problem at 1 second, but this has not happened so far. Beyond 1 second, I have used 4 seconds at a metered 2 seconds with good results and 20 seconds at a metered 8 seconds. On a bit longer exposure I used 45 seconds at a metered 12 seconds with good results.

You could plot these rough times and get an idea of the curve based on this data, but use it with a pinch of salt. These exposures were based (roughly) on the chart for FP4+ and have worked for me.

One word of caution when shooting late or early in the day, watch out for contrast in this situation. The red spectrum will cause a loss of contrast and expanding development is necessary.

[David A. Goldfarb]

Look in any old book on photography, and you'll get a chart similar to the one posted by Scott Killian. Before the age of T-Max, Provia, and other films with really outstanding reciprocity characteristics, most B&W films were pretty similar in this regard.