Film spectral sensitivity
Not every black-and-white film sees every colour. Choose a film type to see the range of wavelengths it records on the visible spectrum — which is why orthochromatic film renders red as black.
A schematic of the general sensitivity ranges by film type, not a measured emulsion curve — individual films vary. It explains the classic behaviour: ortho film is safe under a red safelight and turns red subjects dark; panchromatic sees the whole visible spectrum.
About this tool
Not every black-and-white film sees every colour. This chart shows the general range of wavelengths each film type records on the visible spectrum, from blue-sensitive and orthochromatic to panchromatic and infrared, so you understand why ortho film renders red as black.
How to use it
- Choose a film type such as orthochromatic or panchromatic.
- See its sensitivity range highlighted on the spectrum.
- Read the wavelength range and the behaviour note.
- Compare types to understand filters and safelights.
FAQ
Are these measured emulsion curves?
No. They are schematic sensitivity ranges by film type; individual films vary, but the ranges explain the classic behaviour correctly.
Why can I use a red safelight with some films?
Orthochromatic and blue-sensitive films are not sensitive to red light, so a red safelight will not fog them; panchromatic film must be handled in total darkness.