The NIR ones were taken with a 87 filter. The "colorized ones" are a combination of two shots. One in NIR one in regular color. I convert both to Lab and use the L channel from the NIR one, and the a and b channels from the color one.
This uses the luminance from the IR but preserves the "normal" color.
Glad you liked my gallery. I find looking around pbase to be a great learning experience, and I enjoyed your gallary on guitars.
I found your gallery after your comment on my guitar study - I'm glad to see it! I especially like these shots. The NIR ones - were they taken with a filter, or post-processed that way?
Keep up the great stuff!
ruthemily