This post is to compare the B+W 090 & 091 Red filters for use in a Full Spectrum IR camera system. The 090 (590 nm ) and the 091 (630 nm) are not far apart in frequency, but the overall results are strikingly different! I personally am leaning towards the 090 filter for my own use but can see where the 091 has some uses. First off, the 091 gives a slightly more subdued color set right out of the camera with the blues leaning slightly towards green. The Reds are softer and present a more gentle image overall. For Faux and B&W work I think that the 090 gives slightly better results overall.
Here is an image from the 090 filter:
As you can see, the 090 gives a richer color set for Faux Processing and you have a little more to work with in Photoshop. Overall this filter has turned out to by my main work horse and it lives on the camera most of the time!
As you can see, the reds and yellows are lighter and more subdued. This image was really pushed in CS5 in order to bring out the colors to get them as close to the 090 as possible but there was no way to get them there. I do like the affect though. Here is the original image without the color push:
B+W 091 Normal processing:
I hope that you have enough information to make a decision on these 2 filters from B+W. To me, the 090 is slightly more useful but I will keep both in my kit!