A pro who's been helping me a lot - Jim Brozek - found the answer. That filter will not work with grayscale images. Therefore none of my scans of B&W negatives were working unless I'd inadvertently made them RGB. Similarly, conversions of digital files to B&W either through Channel Mixer or through a Nik filter would work if I left them RGB (which is the default), but I have tended to change the mode to grayscale. Therefore the solution is to change the mode to RGB in order to use the lens correction filter.

Alex,

There are other reasons in my opinion why you NEVER want to transform an image to the grayscale mode. Many printers exhibit a terrible color cast when you print a B&W image in the grayscale mode, but do a decent or excellent job when printing a B&W image in the RGB mode.

Frans Waterlander
pixographer

Thank you very much for replying, Frans. I'd thought that because I print with K3 inks on an Epson R2400 that it did not matter, but you have me curious. I'm rescanning some negs and re-doing from RAW and comparing. So far what seems to be happening, which seems odd (but then I obviously have a lot to learn) is that the color cast seems different on screen (a LaCie, albeit a lower model - the photon19vision) but the prints are very very hard for me to distinguish. I am continuing at it though and will lean to the RGB anyway. Thanks again.

Correction - Frans, I am seeing the differences as I print a few more. Curiously the man in the street (actually my college students) tend to prefer the grayscale ones, but I prefer the RGBs. The former are darker (even setting the printer one step lighter) and tend to show more detail in the midrange, but the RGBs are snappier. Neither have any colorations worth mentioning using the K3 inks. (All 8 inks do get used though to my initial surprise.)

Alex,

You should read your printer's manual carefully to see what Epson recommends for printing B&W images. For my 2200 using grayscale is disastrous and Epson tells you to use RGB. For your printer that may be different, I don't know, but the fact that results are noticeably different between the grayscale and RGB modes tells you already that you need to better understand what is going on/advised by Epson. All inks, including the blacks are used in an Epson K3 printer unless, for B&W images you tell it specifically to only use the black inks, so you should look into that also. I would expect some color cast if more than the black inks are used; the degree to which this is obserable may depend on what lighting you use to view your prints.

Frans Waterlander
pixographer