BW-Noise Addition Gimp

[willgoss]

I thought that the noise addition discussion could be expanded to include Gimp.....There is a plug-in GIMC that gives a nice selection of BW conversion options.......

Below I have included it's image set for Channel Mixer settings 25,35,40 which is appropriate for Kodak Tri-X 400 and below set the grain for Shadows, Mid Range and Highlights....



The following is some of the Grain Addition settings..........



The PS-Type Plugin Xero has a filter Art Grain that ALSO CAN BE USED.....are some comparisons with the GMIC settings......both allow adjusting the amount of noise by luminosit6y........

[David]

Hi Will - You've beat me to it on this one. Following the discussion re B/W noise I had a quick look at the GMIC option yesterday and thought that it required more study than I could give it at the time. I also had a look at OptikVerve (Google and ye shall find if you don't already have it) as it has some "film" options. I wonder if the noise discussion is really to do with the distribution of grain across the surface of a film. Whether this distribution is uniform, Gaussian, or what I cannot fathom at this point. It is almost certainly not Gaussian and I'm pretty sure it's not uniform either. It probably is truly random and requires a true random generator to position simulated noise grains.

Anyway, perhaps the GIMP and GMIC will through further light on it.

Cheers

David

[willgoss]

Yes David I do have and did test VP......

I found the effect very mild and does seem to increase toward the shadows...It seems to be uniform in type.....I do like the conversions using Film 1, 400 ASA and their sepia.......great place to start,,,,,,,

I also tried PSP Noise which seemed to give me the nicest results....it is much like Gimp Uniform at 20-30-10 when set to 20.........