Filter Question: Y1, Y3, O1, G1, R1, etc.

[rguinter]

Greetings:

I have a number of colored filters in various thread sizes that I use on my various MF and LF lenses. Many of them are labeled: Y1, Y2, Y3, O1, O2, G1, R1, etc.

Regarding the numbering system: specifically the Y1, Y2, and Y3 (yellow), does anyone know where I can find the percent transmission curves for these? I can see obviously that the Y3 is darker yellow than the Y2 which is darker than the Y1, etc.

But nowhere do I recall ever seeing transmission curves for the various ratings.

Would help me a bit with my shooting if I knew the cutoff values for some of these.

Many thanks to anyone who can help.

Cheers,

Bob G.

[Mark Stahlke]

Appendix 4 of The Negative by Ansel Adams shows the spectral characteristics of some common filters. The filters are listed by their Wratten numbers. I don't know how to translate your filter designations into Wratten numbers, so I don't know how much help that will be.

[Peter K]

On the website from Heliopan (http://www.heliopan.de/produkte/schwarzweissfilter.shtml) you can find some transmission curves of b&w-filters with the Wratten numbers in parentheses. Y1 = 5; Y3 = 12; O1 = 22; G1 = 11; R1 = 25.

[Don Wilkes]

See if you can find a copy of Kodak publication B-3, KODAK Photographic Filters Handbook.

[W K Longcor]

See if you can find a copy of Kodak publication B-3, KODAK Photographic Filters Handbook.

Yes! There was more good knowledge in those Kodak handbooks than most people realized. Find an old retired photographer and see if you can buy his complete collection of Kodak handbooks -- but just for the record -- even though I'm retired, I'm NOT parting with mine!:D

[Ron Marshall]

Scroll up and down for the absorption spectra:

http://books.google.com/books?id=MzN1AAAAMAAJ&pg=PA7&lpg=PA7&dq=wratten+filter+absorption+curves&source=bl&ots=HPCiccV-Uj&sig=76JgvQhpIznFju1y7Ystd0EOOl8&hl=en&ei=MQqmSenHNZnMsAOu8fTsDw&sa=X&oi=book_result&resnum=1&ct=result#v=onepage&q=wratten%20filter%20absorption%20curves&f=false