Infrared Independent Study
John Bright
Spring Quarter 1999
Instructor Bill Schneider
Click here to view photos done for this study.
Objective: to determine a procedure of accurately exposing and developing
black-and-white infrared film using infrared flash as the main source of exposure.
Purpose: to use infrared flash photography to obtain photos of subjects in dark atmospheres without the interference of visible flash. The use of infrared flash, which is invisible to the human eye, should make it easier to get more natural photos of people, especially in circumstances where they would tend to be more aware of the photographer.
Conclusion: After three studio tests and three field tests, the study proved very effective.
Using Kodak High Speed Infrared black and white film combined with flashes filtered with infrared #87 filters, it was possible to obtain easily printable negatives. In addition subjects did not appear to notice the flash. By using the Konica Hexar camera, which can be programmed to autofocus for infrared film, it was possible to photograph people without putting the camera to the eye (see results of Field Test #3, most of which was shot in this manner).
Photos were taken of people as close as two-feet, the minimum focusing distance of the camera, and they did not seem to ever be aware of photographs being taken. There were several drawbacks to the process however.
1. The film has a very grainy look, approaching that of T-Max 3200 film and has a more limited tonal range compared to conventional black-and-white films. Also, the infrared spectrum, when made visible, changes the tones of grey from what the human eye sees. For example, a black item of clothing might appear medium grey.2. The film also records a soft haze around people's skin and also around white objects.
Overall, the study was very successful in finding a useful and consistent method of
exposing infrared film to infrared flash. It should prove useful in future documentary
work.
The following pages are the methods used in each test:
Infrared Test #1
Test constants - Film exposed in a Konica Hexar, in darkened room, using a Vivitar 283 at
seven feet, full power, with an 87 filter as the only light source. (Minolta Flashmeter
read f 1.4 and 5/10ths at 100 asa).
Variables - the variables were the films; Kodak IR Film and llford SFX200 were exposed twice each with the other variable - f-stops of f2, f2.8, f4, f5.6, f8, f11, f16, and f22. Then each brand of film was processed in D-76, diluted 1:1 for 13 minutes and also for 9 minutes. Agitation once a minute for five seconds. Thus the combinations were as follows:
Kodak strip (exposed in one stop increments from f2 - f22) processed for 13 minutes
llford strip (exposed in one stop increments from f2 - f22) processed for 13 minutes
Kodak strip (exposed in one stop increments from f2 - f22) processed for 9 minutes
llford strip (exposed in one stop increments from f2 - f22) processed for 9 minutes.
Results: the llford film did not register any exposure, thus nullifying it's usefulness for infrared flash-lit subjects. It's infrared sensitivity obviously does not extend into the invisible spectrum much. The Kodak film registered at all the f-stop and development combinations, except at f22.
The density looks best at around f2.8 or f4 with the long development time. But the
correct density needs to be determined, either by calibrating the scene with a grey card
or shooting the scene with Tri-x as metered with the incident meter and processing
normally.
Intrared Test #2
Test constants - Kodak high-speed infrared b&w film was exposed in a Konica Hexar, in
darkened room, using a Vivitar 283 at seven feet, full power, with an 87 filter as the
only light source. A grey card was photographed.
Variables - there were two variables - the exposure and two developers used (D-76 and T-Max). Two film strips were exposed at f2, f2.8, f4, f16 and f22. The infrared flash trigger on the camera was deflected away from the grey card. But additional exposures were shot without the 283 flash, and without deflecting the trigger so as to see what the exposure of the trigger's light would be. The test combinations were as such:
Kodak HIE film (exposed at f2, f2.8, f4, f16 and f22) - processed in D-76 straight at 75-degrees for 7 minutes.
Kodak HIE film (exposed at f2, f2.8, f4, f16 and f22) - processed in T-Max developer diluted 8:1 at 75 degrees for 8 minutes.
Results: Both developers gave a good density to the negatives The f4 densities (over film
base fog) were 1.01 and 1.06 respectively. This was a little to high for a medium grey. It
was later determined that the camera angle through the flash card to the flash was about
90-degrees, resulting in a higher than normal density because of a reflective highlight on
the grey card.
Infrared Test #3
Test constants - Kodak high-speed infrared b&w film was exposed in a Konica Hexar, in
darkened room, using a Vivitar 283 at ten feet, full power, with an 87 filter as the only
light source. A grey card was photographed. The film was processed in D-76 straight at
75-degrees for 7 minutes.
I also ran an exposure test using Tri-X and shooting a grey card at normal exposure, -5 stops and +4 stops. This allowed me to establish a density to shoot for in the infrared film.
Variables - the exposure was the only variable. The film was exposed at f2, f2.8, f4, f4.5, f5.6, f5.6-1/2, f8, f8-1/2, f11, f 16 and f22. The infrared flash trigger on the camera was also filtered with #87 filters. But additional exposures were shot without the 283 flash, and without deflecting the trigger so as to see what the exposure of the trigger's light would be at a distance of one foot. Then a series of portraits were done to see some real results and to test the accuracy of the Hexar's infrared focusing mechanism.
Results: The exposure of f4 gave the best density of 0.70; compared to 0.91 for f2.8
and 0.64 for f4.5. (medium grey in the normally exposed and processed Tri-X was 0.69) The
exposure of f4 in the portraits also gave the best density for the whites. The accuracy of
the camera to focus for infrared in nearly no light was impeccable. A slight haze is seen
around the subjects however and might be reduced by attaching 120-film backing to the
camera's film pressure plate for the next shoot.
Infrared Field Test #1
I finally put the film to a real test in the field in which it was intended - a dark bar.
Before going into the field I first calibrated my meter so that it could be used to accurately predict exposure. To do this I set one flash at full power, ten-feet from the meter. Knowing that a good exposure was f4, I adjusted the meter's asa setting to match f4. This gave me a film speed of 1000, which of course is only useful for these flash units and filter combinations, and only when ambient light is not predominant.
Also, l taped black film-backing paper from 2-1/4-roll film to the film pressure plate of my Hexar. This is said to reduce the halo effect caused by the lack of an antihalation layer in the film.
I first photographed using two infrared filtered flashes aimed toward my subjects
within a distance of 12 feet, giving an exposure of about f4-1/2. Later I used one-flash,
bounced off the ceiling and wall, to give an exposure of around f2-1/2.
The film was processed in D-76 straight at 75-degrees for 7-minutes.
Results: The results were quite good. Although a lesser percentage of shots were
properly focused, the ones which were sharp looked extra sharp and less "foggy"
due to the added paper in the camera to absorb light causing halation. The only concern is
of high contrast, which resulted in good prints being made without any filtration. It
would be nice to somehow lower the contrastiness of the film. Next time, a film speed of
800 and a decrease in development might be effective.
Infrared Field Test # 2 and 3
The film performed well again.
For the second field test used my meter to measure exposure. In the third field test, I
used a guide number successfully.
In an attempt to lower contrast, have lowered my ASA to 800, and shortened my development
time to 6 minutes at 75-degrees in D-76. However I assume that I cannot get much better
result given the high contrast characteristics of the film and the high contrast of direct
flash. Bounce flash is preferable, but is limited to places with nearby, light colored
surfaces, which is hard to find in a bar atmosphere where this flash technique is
advantageous.
I also discarded the backing paper on the film pressure plate. It seemed to have little or
no effect. I should experiment with other materials.