Rollei IR in Diafine: Failure. Recommendations

[NiallPhoto]

I eagerly anticipated the results of my Rollei IR tests but was disappointed.

1. checked filter factor for Hoya RM72 filter: 2 2/3 stops. check
2. metered at the Rollie recommended rating ISO 64. check
3. exposed for ISO 64.
4. developed as per Rollei instructions (develop at ISO 200) used Diafine 3+3
5. examined film: extremely underexposed.
6. fought back disappointment.

My assumption is that my interpretation of the instructions was wrong. I assumed that the
manufacturer rated the film as ISO 200 then with the filter factor it's ISO 64.

My next test is to meter at ISO 64 THEN add the 2 2/3 stop filter factor making
the effective film speed rating ISO 10.

Anybody have any experience with this film/developer combination?
Am I totally off base here?

[NiallPhoto]

Just found this.
So looks like ISO 6 was used. Will test at 6 and 10.


http://www.largeformatphotography.info/forum/showthread.php?t=29039&highlight=Rollei

[RDB Korn]

I've been doing some testing with the Efke IR film, Hoya RM72 filter and Thornton 2 bath developer. The last time I was out, I set my meter for ISO 6 and took three exposures: meter reading, +1 stop, +2 stops. Film was developed 5+5 in Thornton 2 bath in a Jobo drum with constant agitation. The best exposure with this combination was +2 stops.

[Jim Graves]

I've always used Rollei IR with a 25 filter (much lighter than the RM72) ... Rated it at EI 50 and it was perfect. So, 6 sounds about right.

[Glenn Thoreson]

Something sounds strange about your filter factor. A red 25 requires a 3 stop increase in exposure with normal pan film. The RM72, if I'm not mistaken, is so dense as to filter out most visible light, thus requiring much more than 2 1/2 stops or so. That would explain your under exposure problem. Or am I wrong about this?

[al olson]

Although there is some confusion with regard to origins of the MACO/Rollei/EFKE emulsions, it is my belief that it is only a difference of branding/rebranding. I have not used the Rollei (I was told by a salesman for Freestyle that it is not a true IR film and it is very insensitive in the IR region). I have used both MACO and EFKE brands and my experience is similar.

Using a #25 filter with these emulsions does not produce the Wood effect. It hardly even darkens the sky. That is because the spectral sensitivity of the IR is much less than the visible red. It is necessary to use an R72 or equivalent to bring out the Wood effect. To get the appropriate exposure I have to rate MACO/EFKE at EI=1.5, see the accompanying photo.

I am developing this film in 1:1 D-76 for 13:30, a couple of minutes more than they recommend. To get the desired IR effects, an EI of 1.5 necessitates a very slow shutter speed, which makes it difficult to avoid motion blur with moving vegetation.

[Vlad Soare]

ASA 64 is extremely optimistic for Rollei IR with an opaque filter. I have got good results with the Rollei Infrared at EI 6. At EI 12 it was still printable, but clearly underexposed.
Rollei IR is an excellent film in 120 format, but I hate the 4x5 version because of its extreme thinness. I simply hate it and will never, ever, buy another box. I like the film and will continue using it, but only in 120.