I have used a Peak viewing filter for years. It is about a Wratten 90 color. It works for me and I like it fine. I'm thinking about getting another one for the other camera bag and I got to thinking about why are viewing filters amber colored. Film 'sees' mostly in the blue and blue-green and our eye sees mostly in the middle green. It would make sense to use a blue filter as a viewing filter. Then you eye would see what the film sees. So why the #90? Anyone know?
I have looked around at viewing filters and see the Peak filter is still available and a Tiffen (and ZVI, but no thanks) and from the movie business there is Harrison & Harrison. H&H make a whole lineup of colors for viewing filters.
Any input would be appreciated.
Isn't the #90 the Kodak viewing filter? Wouldn't surpise me that after many tests that's what they decided on. I wonder if they ever published the studies.
I remember reading about the Zone IV viewing filter and the suggestion was this color and density would give you an approximation of what the tonal range of the photograph will look like in Black & White.
It would be interesting if there was more technical information available for how this color and density was arrived at.
From experience the above is right. Lee showed me how to use one and it really brought to light the lack of tonal range in the subject we were observing. A valuable lesson.
If my memory serves me correct, the #90 viewing filter is of a color that has approximately the same compensating effect on both red and green in the visual spectrum. Therefore it will not give an erroneous compensation to either extreme when used as a viewing filter. If one were to use green, for example, the green portions of the object would be lightened and the red would be darkened. This would give a tonal representation that is skewed.