I think the thing I like most about working in black-and-white is the fact that it's much more an expression of how I feel about a subject than a representation of "reality," as is so often the case with color photography. The world doesn't exist in Black-and-White (my mother told me that...) so a B&W image is by its very nature an abstraction of the things we see. The judicial use of filters can greatly enhance the impact of how a subject appears, and in black-and-white we can even skew the way colored subjects relate to each other. I normally like to be fairly subtle about my use of filters; a photograph shouldn't look like a filter was used, just as a print shouldn't look like it was dodged and burned! One of the most generally popular choices, a #8 Yellow, is usually so subtle that I don't see much point in using it. Another popular choice, the #25 Red, is often too strong, rendering skies and day-lit shadows illogically dark. My two favorite filters, a #12 Yellow ("minus blue"), and a #23 Red, respectively, have both more strength and finesse than the ones found in most camera bags. The #12 yields an effect almost as strong as a #15 orange, but with only a 1 stop filter factor, only slightly greater than the #8. The #23 tends not to make skies quite so artificially dark as the #25. Of these two "favorites" I would say that I use the #12 for most of my landscape work, with the #23 for most of the rest. I sometimes use a #15 if I want an in-between effect or a #25 if a subject needs a bigger kick. Occasionally I use no filter at all. Green filters can sometimes be useful in dealing with foliage, but be aware that the "greens" we see in plants and trees often don't have the true spectral qualities to make them respond to filtration like we think they should! By the way, the #s 12 and 23 filters were Ansel Adams' favorites. That's how I discovered them. General Filter Information © Alan Ross Photography Workshops In Black-and-White photography the practical effect of a filter is to lighten its own color and darken its opposite color. In purely scientific terms, a filter has no effect on its own color and darkens everything else, including "neutral" colors. When we apply a "filter factor" to the exposure, neutral colors remain unchanged and then the filter's own color becomes lighter and the opposite becomes darker. The color wheel below shows the relationships between the Additive Primary colors, Red, Green and Blue, and their Subtractive Primary (opposite) counterparts: Cyan, Magenta and Yellow. Red is opposite Cyan Green is opposite Magenta Blue is opposite Yellow What we commonly call a "blue" sky is actually a bit more cyan, which is why a red filter will darken the sky more than a yellow filter. Orange is in between. Keep in mind that outdoor shadows are illuminated by the sky, not the white light of the sun. Any filter that darkens the sky will also darken the shadows! Green or red filters can be quite useful in the Southwest where we might come across a brilliant green plant in front of a red sandstone wall. With no filter used, the BW film will see the green and red as being the same: gray mush. A strong green filter will make the plant light and the sandstone dark, the red filter will make the plant dark and the sandstone light.