What are the reciprocity corrections for Rollei Pan 25?

[Treymac]

Hey guys. So I'm going to be shooting long exposures in the daytime, possibly around 8 - 15 seconds. But I don't know what kind of corrections I need to make for the Rollei Pan 25 film. Does anybody know, or know of where I kind find them?

Thanks.

 

[Treymac]

Does anybody know where I might be able to find out the reciprocity failure corrections?

I could also use Rollei Ortho 25 if that's easier to find the corrections for.
Thanks.

 

[JSebrof]

Not sure, just tried looking and couldn't find and official data anywhere. This page here:
http://www.stevehuffphoto.com/2010/04/10/low-speed-film-fast-lenses-by-max-marinucci/
seems to indicate 1 1/2 additional stops for between 10 and 100 seconds, and 2 stops for over 100 seconds. You could contact him for where he got his information.

 

[AgX]

That Steve Huff mixes up films.

 

[Treymac]

That Steve Huff mixes up films.

How so? What's happened in the past?

 

[Treymac]

Ok, so whatever film I use, I`m just going to assume to make a correction of around 2 stops. That seemed to be around what I did with Delta 100, and I don`t think that with shutter speeds between 10-15 seconds, an extra stop will make a lot of difference.

 

[AgX]

Treymac,

He says that ATP and (Kodak) Technical Pan are essentially the same. They aren't. They have different characteristics and are decennias apart. And Rollei Pan 25 is not repackaged APX25.

 

[marco.taje]

I don`t think that with shutter speeds between 10-15 seconds, an extra stop will make a lot of difference.

Just for the sake of correct logic, I'd like to point out that one stop is one stop, regardless of the overall brightness. With your time being 10-15 seconds, one stop will give the same difference if the time was in the 1/1000 seconds range.
That's why we measure differences in exposure in stops and not seconds.

My 2 pennies.

 

[Paul Sorensen]

Since you are probably dealing with a traditional grain film, I would probably lean toward a large adjustment. Personally I would test it at 1 and 2 stops of correction at 10 seconds. It may need more at 15. If you can't test it, you can always bracket.

 

[Willie Jan]

I guess it also depends on your developer and method of light measurement.
So best way (if you do not have a density meter) is to test it with a gray card and compair it with the same neg shot at for example 1/60 and one at 10sec with adjustment.
Make an test strip where the 1/60 shot has the same gray as your gray card, and make a print of the 10sec at the same time.
They shoud have the same gray tint if done correctly.

for ilford fp4+ 4sec = 10 sec
agfa apx 100 4sec = 8 sec
adox chs 100 4sec = 5 sec
Fuji acros 4sec = 4 sec

 

[Treymac]

Ok guys, tell me,

should I go with Pan or Ortho?