Does any filter enhance yellows in B&W?

[Vonder]

A while ago I went and put together a few shots that show how different B&W filters affect colors in an image, and I put them online at:

http://www.wolfeyephoto.com/BW_Filter_Effects/filters.htm

Unfortunately, there are no light yellows in the test subject, and on the orange colors, little effect can be seen. Is there a filter that has a noticable effect on the yellow spectrum?

 

[David A. Goldfarb]

Yellow darkens blue; blue darkens yellow.

 

[Vaughn]

I use a yellow filter to enhance yellows in the landscape every fall. The redwood forest have the Big-leaf and the Vine Maples, cascara buckthorn, and several berries with leaves that turn yellow through the Fall.

The yellow filter makes the yellow leaves just pop in the landscape -- surrounded by greens.

Check out the link below...the yellow filter did a great job on the yellow vine maple leaves surrounding the redwood. Sorry I do not have an example of this without a yellow filter -- but to get that sort of light value without a filter, I would have had to increase the contrast of the entire negative, or used some other control that would have more effect on the rest of the image.

(there was a url link here which no longer exists)

Vaughn

 

[hrst]

This is a very basic and simple question.

Filters work by reducing some wavelengths. A yellow filter passes yellow and filters out (darkens) others, especially blue. A blue filter passes blue and filters out (darkens) others.

Every person has a different meaning for "enhancing", but if you want to affect yellows, you can;

Lighten yellows by using a yellow filter, however the effect is quite subtle as yellow is quite a light color to begin with;
Darken yellows by using a blue filter (opposite color to yellow, you see), effect is quite dramatic because you leave only the part of image which usually has the least significance (blue).

This simple theory can however be extended to much more complex science. For example, filters which look exactly the same with bare eye can produce clearly different results if the have different spectral response (narrow vs wide or multiple peaks). And we could discuss for hours about theory of color vision. For example, in natural shots, the primary colors have the importance in this order; green, red, blue. So, by removing blue with a yellow filter, the effect is usually most subtle, and this is used as a "default" filter by many. By removing green and blue with a red filter, effect is dramatic but still very usable. By removing red and green by a blue filter, the effect is usually over-dramatic. These are of course generalizations (just like the "contrast control properties") that depend on scene. This cannot be stressed too much. If you photograph a grey wall, filters won't do anything to contrast or any property of the picture; and if you photograph a blue wall, using a blue filter won't make any drastic effect.