I normally use red, orange, green, and occationally polarizer filters with my B&W landscape work. On a dark, overcast day, is the use of filters greatly diminished, or just subdued? Is it worth it at all? (aside, for example, of a polarizer taking the sheen off surfaces, etc.) I know, I should run tests, but time is tight, and I appreciate the expertise of this forum ! thanks mark smith

-- mark smith (msmith@fayar.net), May 28, 2002

Answers

The polarizer will do nothing for the sky, but will still work to cut glare from reflective surfaces.

Other filters will work as normal; that is, they will lighten the same color (as the filter) and darken the opposite color. So a red filter will still make green foilage darker and the red apple lighter. But since there is little color in the sky, filters will make little difference in how the sky is rendered. Actually, if the overcast is not even, a red filter can sometimes bring out details in clouds that you didn't even know were there, but don't expect it to be dark.

David Carper ILFORD Technical Service

-- David Carper (david.carper@ilford.com), May 28, 2002.

A Polarizer will take a small bit of the sheen off the foliage but as David says, the used of the red will probably do more good. Also, to give more punch to what could be a really dull negative if developed normally... push it about 10-15%.

-- Scott Walton (walton@ll.mit.edu), May 28, 2002.

Mark, Be careful with exposure when using filters on cloudy days. Since the light on an overcast day is much bluer in quality than on sunny days, the filter factor for all blue-eliminating filters will be increased. This includes yellow, orange, green and red filters. The opposite happens with blue and cyan filters. I use a Zone VI modified meter and read through most of my filters, which eliminates the problem, but if you apply factors, adjust them for cloudy days. It's better to err on the side of overexposure or bracket if you are not sure.

Is it worth it? You bet. Yellow to red filters can eliminate a lot of haze (which is mostly scattered blue light), increase contrast between bluer shadows and more brilliantly lit highlights and gratifyingly darken the darker clouds in an overcast sky (which are usually bluer due to the removal of the longer wavelengths by the water vapor in the clouds. The thicker the cloud, the bluer the light). Film is cheap; take one with and one without to see the difference.

Regards, ;^D)

-- Doremus Scudder (ScudderLandreth@compuserve.com), May 28, 2002.