Infra-Red Photography FAQ

This FAQ is organised into the following topics:

  1. Introduction
  2. Contributors
  3. Why IR?
  4. Subjects
  5. What about heat?
  6. Which IR films? - the options
  7. Which cameras?
  8. Which lenses?
  9. Buying and storing
  10. Loading
  11. Exposing - filters, rating
  12. Focusing
  13. Flash
  14. Developing
  15. Printing
  16. Examples
  17. More Infrared info
  18. Mailing list
  19. Ultraviolet Photography

These cover most of the topics of the frequently asked questions about IR photography on rec.photo.

Original post (official site) (local copy)

  1. Introduction

    This FAQ was originally compiled by Caroline Knight (CK).

    Rui Salgueiro (RS) is translating it to HTML.

    CK: Sometime ago I promised to write an IR FAQ. I wrote this and sent it out to various people but have had no replies. If you can help with the gaps or put me right where what I wrote is wrong - please do!

    As to where it should end up I assume that all FAQs once real should be posted to rec.photo.help

  2. Contributors

    This FAQ is intended to draw together net.wisdom on the topic of infra-red photography. I had a rather bumpy start so got more than the average amount of advice on the subject. Putting together this FAQ is my thank you to everyone out there who helped and encouraged me, including but not limited to:

    There are currently some blanks that I would like to fill. These are shown by <>'s with text inside indicating what sort of thing I'd like to fill that slot with. Any corrections/additions or other comments are welcomed. Please send to rps@mat.uc.pt .

  3. Why IR?

    Infra-red photography uses films that are sensitive to both the light we can see and some of the longer length (above 700 nm) infra-red radiation. The film is also sensitive in the UV region (below 400 nm). In the case of the Kodak HIE film it is sensitive to near-infrared radiation out to 1000 nm wavelength (1 micron) roughly. There are scientific uses for such films but here the main use is to expand our range of picture making media.

    Some people just try IR once as a novelty others get hooked on the effects and exploit it as their main film, especially Kodak's High Speed Infra-Red black and white film.

  4. Subjects

    Everything looks odd on colour IR film. The following remarks relate to black and white IR film.

    Vegetation and sky look very different from normal therefore incorporating either or both into your pictures will take advantage of the effect of IR film. Vegetation comes out bright, clear sky comes out dark - clouds stay light.

    Skin also looks different on IR film (it reveals veins under human skin) which can be used for interesting portraits.

    Topics suggested are:

    The gimmick with sunglasses is easily explained: (gradually) grey filters used for normal optics (photofilters, sunglasses) don't have any effect on IR waves; this non-effect is also seen with polaroid filters (it could have been polaroid sunglasses).

    Hints

  5. What about heat?

    Thermal radiation will not show up; IR films are not sensitive to a long enough wavelength to show such things as heat patterns.

    Heat sources from things like engines put out most of their radiated energy in the far-infrared, in the wavelength range of 10-100 microns or so. To detect this you need special infrared sensors, and generally they have to be cooled with liquid nitrogen or other temperature regulators that can get you well below 0 C. (Just as the inside of a camera has to be dark, the body of an IR detector intended to detect heat has to be cool ...)

    Another way to look at this is:
    if in a dark kitchen you turn your electric stove element onto high and heat it up to the point just before it begins glowing red hot, that is when you finally have enough IR waves being produced in the right wavelength to make a photograh.

    On the other hand, according an ancient copy of the Kodak "Infrared and Ultraviolte Photography" book (1961), IR can be used to photograph self-luminant objects as cool as 250 degrees C. I think I am going to try to photograph hot car parts (exaust system, brakes).

    Heat will however tend to increase the fogging of the film. Keep film as cool as possible and avoid leaving in hot places like in a car on a hot day.

  6. Which IR films? - the options

    There are four black and white IR films from Agfa, Ilford, Kodak and Konica. There is one colour IR slide film from Kodak.

    Kodak High Speed Infra-Red black and white film (HIE 135-36)

    This is available in 35mm (36 exposures), 70mm and 4x5" sheet. (W.J.Markerink said "If you ask nice, pay $$$$ and wait long, you might get larger formats as well....;-)" It seems to be more commonly available than the other IR films. It is grainy, sensitive to IR down to approximately 1000 nm. and is the most used IR film. It has no anti-halation layer thus increasing the need for care when loading and unloading to avoid fogging. I suppose that the lack of the anti-halation layer is also the reason for the 'radiation' effects in the highlights, that is halos surrounding shiny objects.

    Process using ordinary black and white developers. Examples given:

    • HC-110 dil B for 6 mins
    • ID 11 for 11.5 min
    • Agfa Rodinal 1:50 for 10 min

    From the datasheet: 

    	| Small Tank - (Agitation |	| Large Tank - (Agitation |
	| at 30-second intervals) |	|  at 1-minute intervals  |
Celsius	|18.5 | 20 | 21 | 22 | 24 |	|18.5 | 20 | 21 | 22 | 24 |
--------+-----+----+----+----+----+-----+-----+----+----+----+----+
D-76	|  13 | 11 | 10 | 9.5|  8 |	|  14 | 12 | 11 | 10 |  9 |
--------+-----+----+----+----+----+-----+-----+----+----+----+----+
HC-110 B|  7  |  6 |  6 | 5.5|  5 |	|  7  | 6.5|  6 | 5.5|  5 |
--------+-----+----+----+----+----+-----+-----+----+----+----+----+
D-19	|  7  |  6 | 5.5|  5 |  4 |	|  7  | 6.5|  6 | 5.5|  5 |
--------+-----+----+----+----+----+-----+-----+----+----+----+----+
    HC-110 (dilution B) for scientific uses

    D-19 for maximum contrast.

    Your favourite black and white developer will probably work though you may have to experiment to find the right times.

    < Will TMAX dev and other T-grain optimised devs work? >

    It seems that they work:
    "I saw some photos in a camera store recently, and learned that they were 35mm infra red. I could not at first recognize it as IR because the grain was incredibly fine. The photographer (who is an employee at the store) explained that he developed the film in T-Max. Says it gives finer grain with that film than the D76. I do not know what his developing times and temperatures were, but perhaps Kodak could help there." Patricia Trent (PatLTrent@msn.com)

    More about Kodak HIE in Tmax

    Kodak HIE developped as a 1600 ISO slide

    Exp. and Development: Cor Breukel recipe: exp at 200 ASA (depends a bit on which place and what altitude you are); bracket (+ one and - one stop), use red filter (-2 stops), dev: D76 dill. 1:1, 20 deg. C, 11 min

    Important:very gentle shaking, every 30 sec, first 30 sec. continuous (i.e only twist 90 degrees), to prevent "overexposure" at the perforation, due to turbulance (I think)

    Konica Infrared 750 Black & White

    This is available in 35mm (24 exposures) and 120 formats. It is not so grainy as the Kodak film, though still grainy. It is less sensitive to IR so the effects are less exaggerated.
    According to Konica's technical bulletin No. Tech 015 "Konica Infra-Red 750 has a sensitivity range from 640 to 820 nm in addition to the intrinsic sensitivity range of AgBr 400- 500nm. The peak sensitivity is 750 nm hence it's name". However it is also less prone to fogging from stray-light whilst loading not only because it has an anti-halation layer but also because of a better light trap. Kodak's felt trap is considerably more transparent to infrared. It is also less likely to fog due to heat < why? >. Its latency is greater thus get better results if it is not possible to develop immediately.

    I had the information that it is a much slower film, 3-4 stops lower than the Kodak (ISO 12 ?). But Aaron Flin uses it at ISO 32 without filter. From Alex Nanson: 

    The film gives good results with a Wratten 25 filter. Shutter speed
1/60, aperture F5.6 in bright sunlight.

Some suggested film speeds are:-

No filter            32 (daylight)    50 (Tungsten)
No. 25 or 89B        15    "          30     "
No. 87                5    "          20     "

It's not what you'd call fast! But well worth having a look at.

    On the other hand, George L Smyth uses it at EI 10 (with a 25 red filter). "I should mention that this speed (which is partially a result of the developer) is employed in the late spring though early autumn. Early to mid spring and mid to late autumn my speed drops."

    Process using ordinary black and white developers.

      examples
    • Rodinal 1:50 6.5 minutes 20 Celsius when shooting EI 10 with a 25 red filter (George L Smyth).

    Ilford SFX 200 Black & White

    New film available only in 35mm (36 exp.).

    Michael Covington says:
    It's what you might call a "mildly infrared" film. It is panchromatic with sensitivity extending a short distance into the infrared, to about 800 nm. You can use a deep red filter with it and get dramatic infrared-like effects, BUT you can still handle it like an ordinary film -- it does not require loading in total darkness, and it is generally not sensitive to the infrared-only light leaks that plague users of other infrared films.

    Summary:
    - Grain rather fine.
    - Easy to work with. Good pictures of clouds in blue sky with red filter.
    - Severe reciprocity failure; not useful in astronomy (10-minute exposures).

    Alex Nanson says that the sensivity is "upto 740nm". See also:

    Agfa APX 200S black and white

    Spectral sensitivity: the curve starts below 400nm, peaks at 725nm and extends to 775nm.

    Exposure index: ISO 200/24, with red flash ISO 400/27, push development up to ISO 800/30, limit at ISO 6400/39.

    More info

    Kodak Ektachrome Infrared IE (Colour Infra-Red Slide film)

    This is available in 35mm only. < grainy? > < anti-halation layer? >

    When used with an yellow filter this films shifts the colours. Blue is rendered as black, green as blue, red as green and infra-red as red. The film is sensitive up to 900 nm radiation.

    This is processed using E4 . There are very few labs which still offer this old method.

    • Rocky Mountain Film Labs in Denver
    • < examples from various countries >.
    You can also process it at home using an E4 kit, Tetenal make one < check manufacturer and where to get it >.

    See also Bengt Halliger's homepage

  7. Which cameras?

    Not all cameras are appropriate for Kodak IR film use. The other films are less sensitive to IR and have an anti-halo layer so they have less, if any, problems.

    For instance, the Canon EOS models which have an IR optical film loading mechanism (eg Elan/100, A2E/5 but okay in 10s/10 and older models) fog part of the negative.

    [About 4 mm. So you will get a frame that is 20mm x 36mm. The 4mm is in the bottom of the image (top of the film in the camera). (source: a posting in rec.photo (by Vangelis Tziampazis ?))]

    But Mircea Podar (podar@utsw.swmed.edu) says:
    I own an EOS A2 and for the couple of years I had it, I kept regretting that I cannot use infrared on it, according to Cannon. Recently I found on the news that only ~ 1/4th of the frame gets fogged, so I decided to give it a try. Guess what, the ONLY area that turned black from the IR film tracking system was the holed strip and there was NO fogging on the actual film frame!
    I used the Kodak High Speed IR (Black & White).

    negative from an EOS 5/A2
    Negative shooted and scanned by Mircea Podar.

    A previous version of this FAQ said: "Also some camera backs may not be opaque to IR, especially some plastics." No one reported a single case of this happening. For instance, W.J.MARKERINK comments:
    "FWIW: I have used all sorts of IR film in my EOS-1....yes, it has a plastic back, and yes, it has a film window. And no, it works fine, perfectly fine."

    On the other hand, some pressure plates do cause problems with the Kodak HIE film. The problem is the lack of the anti-halo layer. This allows light reflected by the pressure plate (which is usually black, but not mate) to impress the film. This creates the hazy higlights for which this film is know.

    I have read about the Pentax LX or K1000 dimpled pressure plate creating a pattern on the Kodak film (because of the dimples).
    Also some early Minoltas had the same pressure plate for the models with or without databack. The hole in that pressure plate produces a visible effect on HIE film. Markerink says:
    Cameras that are partly unsuitable for IR, Kodak HIE only, are [...] cameras with dimpled pressure plates, like the Pentax K-1000 [...], and (Minolta) cameras with pre-installed databack pressure plates, like early 9xi's and all 700si's.

    You also need manual focusing unless using a very wide lens with small aperture.

    Hints:

  8. Which lenses?

    For ease of focus use wide angle to increase depth of field but don't be put off from using any other lens. It is easiest to use lenses which are marked with a little red mark to show how to correct them for IR focusing. You can use AF lenses to focus then put into manual and reset (so long as they can be overridden).

  9. Buying and storing

    Buy only from places that keep the film refrigerated (or frozen). [Kodak advises keeping the B&W film at 13 celsius or less.] Keep your own film cold until needed. Allow to warm up to room temperature before loading (to avoid condensation).

    If you cannot process immediately return the film to the fridge/freezer.

    Cor Breukel reports: "Temp. sensitivity: I carried this film with me in India, Mexico, Guatemala, Greece, not exactly cool climates, (and also frequent exposure to radiation on the airports) with no apperant fogging. I store this film at 4 deg. C though."

    So, it seems that although it is not recommended to buy this film by mail-order, it is a viable option (and the only in certain countries).

  10. Loading

    The general advice is to load in total darkness, especially the Kodak high-speed IR b&w film. However I have had no fogging through loading in a room which is not pitch black - darkened just not total. This avoids embarrassing problems like putting ones fingers through the shutter ...

    Unload in similar conditions. Return the film to its original container until processing.

  11. Exposing - filters, rating

    All IR film is sensitive to both some IR and visible light. To increase the IR effect one reduces the amount of blue and green light reaching the film, or you can block all visible light and record only IR.

    On the black and white films use a red filter. Which red filter you use will effect the amount of non-IR light that is also recorded.

    Visible light ranges from 400 nanometers (violet) to 700 nm (red). Here is a table with the absortion limits for several filters (I chose the first wavelenght for which the absortion is less than 50%).

    	Wratten #25	600
	Wratten #29	620
	Wratten #70	680
	Wratten #89B	720
	Wratten #88A	750
	Wratten #87	800
	Wratten #87C	850
	Wratten #87B	940
    On colour IR film use a deep yellow filter to reduce the amount of blue - otherwise the results will have a strong blue cast. "I even recommend experimenting with a (light) orange filter." - W.J.Markerink 

    Film            Filter           Nominal ISO/ASA
				non-TTL		TTL*

Konica          <filters and ratings>

Kodak b&w       Without filter	80
		Wratten #25	50		400 **
                Wratten #29	50
                Wratten #70	50
                Wratten #89B	50
	(opaques to visible light)
                Wratten #88A	25
                Wratten #87	25
                Wratten #87C	10
                R2              50
    [* if you are using a TTL meter, the meter sees less light than there is, so you should increase the sensitivity marked by the filter factor. So as the filter factor for the #25 is 3, you should increase 3 stops from ISO 50, that is ISO 400. ]

    [use this numbers as a starting point. bracket around them or make tests]

    [** (from a Usenet posting): "I read an article (I guess it was in one of the latest PHOTO + Labor, german) stating that you can use TTL metering for the Kodak IR film. But, as the light sensor built in the cameras are less sensitive to IR than they are to visible light, you have to set the ASA setting on your camera to values between 320-1000 ASA (depending on the type of camera you use)." ]

    Kodak colour < filters and ratings >

    Whichever filter you use it is worth bracketing as more than one exposure can give you interesting effects - you may end up with several usable results from the same scene. Some people recommend bracketing over 5 stops.

    Another reason for bracketing is that the level of IR radiation is not exactly proportional to visible light thus one's exposure meter can only give an approximation. The amount of IR that reaches your camera is also effected by the distance that it travels through the atmosphere. Thus the distance of your subject will also alter your exposure, follow the guidelines on the enclosed data sheet.

    If you must expose through the lens (and the filter) you will need to adjust the working ISO as the meter is seeing less light though you are (hopefully) still getting all the IR available (limited by the sensitivity of the film and the characteristics of the filter). Thus you need to increase the ISO by however many stops of light your filter blocks eg lose 2 stops, go from 50 to 200.

    Most TTL meters do record IR light, so you can use TTL metering with a visually opaque IR filter. Linearity is apparently no problem, you only need to dial in a fixed overexposure correction. You can easily check the needed correction, by comparing the Kodak guidelines with meter readings. 25 red needs +3 compared to no-filter, but most cameras do that automatically; 87 needs +4; and 87C needs +5. If your camera doesn't read +4 or +5 (very likely) compared to no-filter, then you have to correct till it does.
    Older non-AF cameras generally need less + correction than newer AF cameras, due to IR-blocking filters for the AF sensors. But, if using an opaque-to-visible-light filter (eg Wratten #87) on an SLR you will need to compose without the filter so also set the exposure manually at this point.

  12. Focusing

    The exact point of focus will depend on which filter you use as this dictates which wavelengths are most prominent in your image. Most people move towards or to the red infra-red mark on most lenses. If your lens is missing this mark then nudge it to a slightly closer focus.

    Since the Konica film sensitivity is nearer visible light than the Kodak, IR marks for the Konica film are about halfway between the standard IR mark on your lens and normal.

    To improve apparent sharpness use a small aperture to increase depth of field.

    Another note: don't stop down too far! Diffraction is twice as bad with long IR waves as it is with visible light! Stopping down to minimum aperture is a NO NO!

    Infrared Ektachrome focuses normally. Given the fact that Ektachrome IR records from yellow/orange till the IR region, this is no surprise; it is a compromise between focus of the visible and of the IR. Apo's and mirrors are said to make a major improvement in image quality here! Unlike the b&w IR films, you can't choose to only record IR (and hence focus for IR only).

    < Hyperfocal IR focusing? Anyone have any figures for it? >

  13. Flash

    Flash emits IR along with visible light. You should calibrate your flash for IR film through test exposures. You can use a filter over the flash to reduce or eliminate the visible light output.

    Hint

    * Two strips of unexposed but developed E6 film can be used as an approximation to a Wratten 87 (for more info contact: Andy on andpph@ritvax.isc.rit.edu).

    [Be careful on the frequency of flash use. Someone reported that his SB-24 overheated when using this technique.]

  14. Developing

    Process as soon as possible. This is good advice for any film but especially for IR film which seems to be more prone to fogging and more forgetful than other films!

    Take even more care than usual when loading the film onto a spiral. (I have found that I can get away with putting the leader onto the spiral in a darkened, but not totally dark, room.)

    Beware that not all changing bags and not all tanks are opaque to IR film.

    Some people insist on using an aluminium tank but I have not had any problems using my plastic tank (I do not leave the film in for long and do not put it in direct sunlight etc).

    Develop as appropriate to your film (see under description of film).

  15. Printing

    Choose your basic printing exposure to bring out the characteristics you were using - keep vegetation light and skies dark. This can lead to high-key light portraits, dark moody landscapes and ethereal vegetation. Experiment with your negs!

    As with any black and white print you can also tone or tint the picture to increase its mood or highlight a particular element.

  16. Examples

    I would like to put here on-line examples of Infra-Red phpotography. If you have your pictures on-line or know sites that have pictures, please mail me.

This FAQ was originally written by:
Caroline Knight    HPLabs Bristol UK       cdfk@hplb.hpl.hp.com