Exposure adjustment with filters

[thawkins]

A few weeks ago I posted about going to Europe (Med area) with my M3. I have a boat load of Tri-X film to use. I plan to meter with a hand held Gossen or use the metering information from a DSLR. My question is how much exposure compensation should I allow for the use of a medium yellow filter on the M3?
Eagerly awaiting your responses.

Tom

 

[Roger Hicks]

Dear Tom,

Normally 2-3x, but it depends on (a) the filter (b) the film and (c) the subject matter.

Weak yellow is normally 1,5-2x; medium yellow 2-3x; strong yellow, 3-4x. What does the filter manufacturer recommend? That's usually a better bet than an internet forum.

Cheers,

R.

 

[sevo]

The M3 won't care. Your film will. Unfortunately not all filters are created equal in density and spectral response, nor is film. And as colour filters interact with the spectral sensitivity of b&w film, the lighting will also change matters. The published factors of the film and filter manufacturers should be considered starting values for your own tests - apart from giving a factor for only one half of the film/filter combination, assuming the other to be a (imaginary) standard, they also assume bright daylight conditions.

Fortunately medium yellow is a gently filter with a wide spectrum right around the centre point of the films spectral range - a factor of 2 in daylight, or 1.7-2.5 for incandescent respectively dawn/dusk, would be pretty safe, and TTL metering (or through-the-filter, for handheld meters) will match the on-film results closely.

 

[ferider]

In other words one stop 🙂

 

[tlitody]

In other words one stop 🙂

or one and a half stops. Better to err on the side of a tad of over exposure than a tad of under exposure.😉

Remember that yellow, orange or red filters in B+W photography are all minus blue/cyan which results in blocked up shadows in daylight if you don't give enough compensation. Daylight shadows usually contain a lot of blue/cyan. That may be what you want or it may not.