I'm looking at some Kodak filters. The numbers aren't on the list on the Kodak website. One might be for a safelight [#13] the rest seem even less popular. Do the number follow any sort of rhyme or reason? Can I expect a filter to be similar to the number above/below it? Or did Kodak just assign numbers out of a hat?
The filter numbers that are typically used for contrast control are as follows:
Yellow #8 and #15 (will darken blue in gray tone reproduction)
Yellow green #11 and #13 (will darken blue in gray tone reproduction)
Green #58 (will darken red tones in gray tone reproduction)
Cyan #44 (Will darken orange tones in gray tone reproduction)
Blue #47 (Will darken yellow tones in gray tone reproduction)
Red #25 and #29 (Will darken cyan and blue in gray tone reproduction)
Magenta #33 (Will darken green and yellow green in gray tone reproduction)
additionally, filter 89B is used with IR film for haze reduction and lightening of foliage. The filters most commonly used in Panchromatic film photography are #s 8,15, 25, 11, 13, and polarizer.
One of the local shops is selling some filters. They claim somebody found them in the back room. The numbers don't match any on your list-) But they are close to some. So what I'm wondering are they likely similar to the ones on the list.
The numbers that I posted are the Kodak Wratten numbers. So I can't say what you have found or how nearly they would match the wratten numbers or the spectral response of the wratten filters.
I guess that if the price were reasonable and if the filters were yellow, green, red and blue, that I might consider them. Realizing of course that they may not be the equivalent of wratten filters. Basically yellow and red will darken blue skys (the red more so then a yellow) Green will tend to slightly lighten green objects in scenes, though not as much as you would think. Films unless identified as orthochromatic are panchromatic and as such are more responsive to reds then to greens.
I have used blue maybe once or twice in over twenty years. So it is not a big use item. Good luck.
These are actually old Kodak filters. I guess from the days Kodak made everything it's customers might want even if the customer didn't know they wanted it. I spent some time checking the google archives. I think I found one reference to one of the filters [a green]. One thing I'm wondering is if they aren't designed for normal photographic use .
I found reference to one today. It's some sort of filter for X-ray film.