BR/A or X-ray reciprocity?

[Scott --]

Hi all -

I'm going to be trying some long exposures with mammography film. I was wondering if anyone had some idea of reciprocity correction for x-ray or BR/A as a starting point?

Thanks.
Scott

[richydicky]

I scour useful bits of information from the internet and keep them as notes but mostly without the original reference. I think this came from Tim Layton or someone else relating to B/RA. It's a shame this film is no longer available.

" I have found the reciprocity failure to track with T-Max 100 making it very easy to use, especially if you have experienced with T-Max 100. My reciprocity chart is listed below:
Metered Exposure-> Corrected Exposure : 1s->1s - 2s->2s - 4s->5s - 8s->10s -15s->21s- 30s->49s
60s->1:47 - 80s->2:30 -100s->3:29 -120s->4:39 -160s->6:45 - 200s->9:30 -240s->12:50"

[Scott --]

Awesome! Thank you so much - that gives me a good starting place. I appreciate the help!

Scott