View Full Version : Choosing Filters

Reinhold Schable
22-Sep-2014, 12:21
For those folks who are uncertain which filter to use, here are spectral graphs for various filters.

A filters effect on the photographic negative depends heavily on the type of film you're shooting.
In other words... the emulsion's spectral sensitivity should be taken into consideration when selecting a filter.
This is especially true when using non-panchromatic films (x-ray, Infrared, Ortho, collodion, etc.).

Consult your films data sheet for it's spectral response curve and compare it to each filters curve.

The heavy dark line is the filters transmission drawn on a 360-750nm colored background.
Panchromatic films are more sensitive in the central portion of the graph.
It's here where most contrast filters are used (Yellow-green/ Orange/Red).

If you're shooting paper negatives, the Blue/Green part of the graph is most important.
Single grade photo papers are mostly Blue sensitive.
VC papers have added green sensitivity.
Orange/Red filters are nothing more than safelights in this case.

The dashed line represents the spectral response for Ilford's Ortho Plus film.
Ortho films can only see Blue/Green light... so Yellow/Red filters are mostly useless.

The 380-520nm outlined area defines the spectral response for typical wet plate (collodion) emulsions.
A Blue filter may make focusing easier by blocking out the distracting Yellow/Red component.