Infrared Technical Notes

It is possible to take photographs by means of the non visible light exploiting the properties of those special emulsions which were originally produced for warlike end scientific purposes. It is the power of the light that allows us to see. The electromagnetic spectrum identifies the wave length corresponding to the light. The visible spectrum stands in the middle. It ends at the wave length of 700 µm - nanometer, a submultiple of meter, is the unit of measurement for the electromagnetic spectrum wave length.
The human eye can “see” the light from violet to red including all the intermediate wave lengths such as blue, green, yellow and orange – it almost sees like a panchromatic film. The infrared film crosses these limits and records beyond the 700 µm up to the photographable spectrum upper limit.

SHOOTING:

Load and unload the camera in complete darkness, when using Kodak HIE, and in softened light for Rollei Infrared.
Expose according to the nominal sensitivity using the filters recommended by the table.
R25/29 = - 3 diaphragms. R72 = - 4 diaphragms.
It is advisable to maintain a balance between light and dark masses while shooting. Expose according to the lights and, if you are using a non built-in light meter, always remember that a red filter absorbs 3 diaphragms and the opaque one for Rollei about 6. At the beginning take photographs only during the warmest hours, afterwards, when you have more practice take photographs at .....any times. Infrared film requires devotion: do not limit to a test roll. On the contrary keep on ceaselessly and leave behind any other kind of film – at least for some time.

DIVELOPMENT:

Refer to the following table with the caution of making a five minutes precautionary soaking in water having the same temperature than the development bath.
During the development first minute the tank has to be stirred in a very slow but continuous way. Afterwards, go on with 10 overturning per minute when using D76 and 5 overturning per minute when using HC110. With Rollei Infrared it's better change the water during the preventive bath to remove the greenish anti-halo.

PRINTING:

Use a number three fixed gradation paper or a multigrade paper using a number three filter.

INFRARED FILM SUMMARY

* Nominal sensitivity obtained by TTL scanning and 29 red filter mounted. Sensitivity that has to be report on the camera ISO indicator.

** These times are valid when you expose Kodak HIE film for 400 ISO. If you expose it to 800, times must be increased of 20%.