Infrared Photography 2

Spectral Sensitivity of B&W Infrared Film

The following table shows the spectral sensitivity plots of several infrared and regular films, and compares these to the spectral absorption plots for various infrared filters.

Wratten #	Film and Color Filter Spectral Curves

Kodak HS IR
Konica 750
TMAX 400
87A
87B
87C
87
88A
89B
70
29
25

The brighter colored areas of the film plots are 0.3 greater than D-min and darker colored areas are 1.0 greater than D-min (or base fog level instead of D-min for infrared film). The dashed lines in the TMAX-400 plot are speculated sensitivity based upon typical panchromatic emulsions as the available sensitivity plots do not contain any information below 400 nanometers. If we can obtain accurate data from the manufacturer this will be updated.

A Comparison of Infrared Filter Absorption Plots.

TMAX-400 used as a mask for Kodak HS Infrared, can cut off the visual spectrum about like a Wratten #70 or #89B filter. Konica 750 can be used as a mask to Kodak HS Infrared. One interesting use would be a false color image where TMAX-400 was the visual spectrum in blue component, Konica 750 was the near infrared (700 to 800 nm) in green component, and Kodak HS Infrared masked with Konica 750 was the far infrared (800 to 900 nm) in red component. This might be an interesting way to photograph vegetation and other infrared subjects. Of course the color or representation choices are completely flexible.


	Previous	Characteristics of Infrared Light
	Contents	*spectral selectivity*
	Next	Spectral Sensitivity of Color Infrared Film

C1997 by Ed Scott - <dotted.dog@worldnet.att.net>

Return to photo.net

Photography