Hoya R72 filter and B&W film?

I know there are many who used the R72 with SFX 200, but what if you use the filter with standard B&W film, such as FP4? Will you get any IR effect? I have a R72. Has anyone tried it?

f/16 said:

I know there are many who used the R72 with SFX 200, but what if you use the filter with standard B&W film, such as FP4? Will you get any IR effect? I have a R72. Has anyone tried it?

Click to expand...

You will get no appreciable "Wood" effect with standard B&W films. In fact, you won't get with much of anything.

The R72 filter blocks light below 720nm, and the film is not sensitive to light above 720nm.

So you end up with little or no image at all.

MattKing said:

The R72 filter blocks light below 720nm, and the film is not sensitive to light above 720nm.

So you end up with little or no image at all.

Click to expand...

This.

Any film, which is not marked as IR sensitive in big, bold letters, probably won't give any image at all if exposed through an R72 filter. It takes appreciable effort to make photographic film sensitive to these longer wavelengths, and only few very special products have emulsions sensitized that way.

You need to look at the spectral response curve for the particular film you are interested in. Manufacturers publish this information and it can usually be found online. If the film has no or very little response you are not going to get an image. These curves are usually presented on a semi-logarithmic graph. So response falls off more dramatically than if the graph were linear. It's not difficult.

You can get IR effects with Rollei Retro 80s and 400s films. These films are also available under different brand names. I think they were originally designed for aerial photography. I'm sure the original name was Agfa Aviphot, or similar. I have used the 400s successfully with the R72. I rated it at about 6asa for IR work. If you search here, and elsewhere on the net, you should find some information about films that will work. FP4, HP5, and Tri-X won't give you anything. I don't know about the Fuji B&W films. If you want to try a particular film with this filter, you wouldn't need to expose the whole roll through the R72. Just try a couple of shots, make notes of what you did, and see what comes out.
Alex.