Filter Question for a particular situation

[Kevin Crisp]

I should know this but I don't, probably because I just don't use filters. I just carry them around.

I want to photograph a very large abandoned industrial building with faded painted signage on one side. The paint has faded down to a light yellow, a little lighter than a typical post-it note.

If I want to darken the light yellow to make it as legible as possible against its galvanized steel background that is not otherwise giving the yellow much contrast, what filter would I use? Red? My choices are light and dark yellow, green, orange, red and blue.

This is black and white, obviously. The film choice on the trip is 100 and the new 400 TMAX and also some of the "old Tri-X." Thanks.

[jb7]

You should have made a poll-
I'd have voted for the blue- one of the 47's...

[Jim Graves]

The Kodak Professional Photoguide says a Blue filter will darken Yellow (and vice versa). Red darkens Blue (and vice versa) and will lighten Yellow.

[Mark Woods]

Blue is the complimentary color of yellow and will reduce the yellow wave length. This is the principle used in color negative film to expose each emulsion layer.

[Jack Dahlgren]

The great thing about filter is that you can hold them up to your eye and see what effect they have.

But yes, blue will darken yellow. Just look on the traditional color wheel and choose the color on the opposite side (so really purple is opposite of yellow).

If the yellow is really faded, then the filter might not have that much effect and you might be better off just pushing the contrast.

[rdenney]

If you want the painted sign to be dark against a light background, pick a time when the galvanized siding is lit by open blue sky (not by sunlight), and use a blue filter. That will darken the sign and lighten the siding.

If you want the painted sign to appear lighter against a darker background, use a yellow filter. But doing so may make it difficult to get the sign down where you have some density to work with.

You should be able to partly visualize the effect just by looking through the filter. If you have time to reconnoiter and have a digital camera, make a digital snap and play with the Photo Filter adjustment layer, or the Channel Mixer with monochrome output. That might given some insight into which direction to go.

Rick "also voting for the 47" Denney

[Kevin Crisp]

Thanks, this makes sense.

[Lynn Jones]

In addition to a 47 or 47B with bw film, I would suggest that you also shoot digital RAW with the white balance cranked up to 8,000 or 10,000.

This will probably allow you to save the painted material and add it to the film image.

Lynn

[Brian Ellis]

About all you have to know when using colored filters for b&w photography is that a filter passes its own color and holds back its complementary color. A color that is passed will appear darker on the negative and hence lighter on the print. And a color that is held back will appear lighter on the negative and hence darker on the print. So to make the yellow sign darker as you said you wanted to do, use a blue filter. Blue will pass blue and hold back yellow because yellow is the complement of blue. And by holding back yellow it will appear lighter on the negative and darker on the print.

[Brian C. Miller]

Well, if you want to take a walk on the weird side, you could photograph in the infrared spectrum. The filters (Hoya R72 or B+W 092) are expensive, though. But the infrared spectrum seems to be pretty good at bringing out things like faded paint and such.

[Andrew O'Neill]

Use a complementary colour, such as blue or green. What colour is the text?