photo:infrared
infrared photography
Introduction:
classic near IR photography requires detection of the 700-900nm range of IR
photography of infra-red region of the light spectrum allows:
unusual landscape photos with false color or unusual monochromatic effects
suggested subjects:
graveyard shots - grass will go almost white leaving the tombstone floating in an eerie space, similarly for standing stones.
derelict buildings covered in creepers - again the contrast of stone and vegetation. See Pete Schermerhorn's excellent
article on castles in Ireland.
people on the beach - sky and skin, water reflecting sky
nudes in a landscape - skin and vegetation and/or sky
haze reduction - only reduces blue haze, but try it
hot houses - vegetation
people with sunglasses - it is sometimes possible to see the eyes behind seemingly opaque sunglasses.
composition hints:
visualise the elements in the photograph by the way that they reflect infrared light.
blues, browns, dark greens in shadow will all appear dark in the final print. Reds, whites, greens in sunlight will appear light in the final print.
the eye is drawn initially to areas of high contrast in a photograph, so frame the elements to lead the viewer into the scene from the high contrast starting point.
try using strong graphical shapes with high contrast to lead the viewer into the photograph and place important elements using the rule of thirds.
finally, every so often throw the rules out and do something just because it feels right or because you want to experiment
portrait photography, esp. to minimise skin complexion problems such as acne.
scientific uses
astrophotography - most nebulae have strong emissions in the infrared H-alpha band
general hints:
there is more infrared light around when there is bright sunlight. This doesn't mean you should avoid using IR film in other conditions but that the effects are stronger when the sun is out.
largest amount of IR: the hours just after sunrise and before sunset (due to the angle of the sunlight through the atmosphere), the effect is most dramatic (i.e deep black sky) when photographing with the sun behind the camera.
an electronic or bulb flash will increase the amount of IR as well as visible light.
Electronic flash guns and flash bulbs emit plenty of infrared light together with visible light. This means that you can use fill-in flash and flash alone for shooting in infrared. You will need to calibrate your flash for the infrared film of choice through test exposures.
The use of flash allows an interesting possibility - you can use a filter over the flash to reduce or eliminate the visible light output and take infrared photos in the dark without any apparent light. This means that you can take photos without out disturbing your subject or alerting them to the fact that a photo has been taken. If there is no ambient light then an infrared filter over the flash gun is all that is required. If there is ambient light then a filter will also be required over the lens as most infrared film is sensitive to some visible light.
thermal radiation will not be recorded by infrared film; infrared films are not sensitive to a long enough wavelength to show such things as heat patterns, however, IR can be used to photograph self-luminant objects as cool as 250 degrees C.
creating a IR-pass filter for an electronic flash:
A cheap and cheerful way of making a flash filter is by using two strips of unexposed but developed E6 film as an approximation to a Wratten 87 (for more info. contact:
Andrew Davidhazy). Be careful on the frequency of flash use.
It appears that one thickness of E6 film is roughly the equivalent of an 87 filter but with a broader spectral response and with some 1% transmission valleys at 500 and 600 nm. Its transmission starts to drop from 1% at 700 nm to about 95% at 800 nm. Two thicknesses of D max E6 are basically visually opaque with transmission starting at 720 nm and dropping quite rapidly to 90% or so at 850 nm.
Basically the two sheets of E6 simply do not have a cutoff as steep as the Wratten filters nor is the maximum transmittance of light as good. But they are serviceable, particularly for placing over a flashgun where the expensive thin gel Wratten filters tend to fry and buckle!
There is another option for the DIY fanatics - paint your own filters and bulbs. The formula for the infrared paint requires a range of chemicals, some of which have to be purchased in bulk. This could be an expensive exercise, however the formula and instructions on concocting the brew are in this
article.
Infra-red filters:
whether using IR film or a digital camera, you need a IR filter which allows IR light but blocks most or all visible light if you want to get IR effect.
the degree of IR effect is higher as the cutoff frequency increases, but the filter also becomes darker so composition through it may be impossible to visualise, necessitating that composition is performed PRIOR to adding the filter UNLESS you have a live preview digital camera that is sensitive to IR (ie. does not have an IR blocking filter as most have).
as infrared filters get very expensive above 58mm and in most SLR cameras are too dark to compose, consider hand held square IR filters such as Cokin 007 (#89B), Heliopan RG715 and Infrarex IR filter set of red (RG1), dark red (RG2) and black (RG3) but note that the RG3 is of no use on the Rollei IR 820/400 IR film but may be of use on some digital cameras.
red filters:
general notes regarding use of these filters:
Hoya 25A (Wratten #25):
Wratten #29 (B&W #91):
Wratten #70 :
B&W 092 (89B, RG695, Cokin IR007):
dark red filter is for black and white infrared films and filters at light below approximately 650nm. It allows pictures of a pure red image while making good use of the relatively low sensitivity of infrared films. Filter factor is approx. 20-40
good IR for Kodak HIE and Konica 750 film
not really deep enough for digital IR
blocks nearly all below 650nm;
blocks ~50% between 650-700nm;
blocks ~10% between 730-2000nm;
usual "infrared" filters:
more extreme IR filters which may not work on some digital cameras
filters which are too extreme for current films but were good for Kodak HIE
Infra-red film:
IR film has an emulsion that is sensitised to respond to a wider range of light and radiant energy than standard film, allowing it to record not only visible light, but also the near infra-red end of the spectrum.
in contrast, normal “panchromatic” B&W films record only to about 700nm & eyes are sensitive from ~400 to 760nm
it is a B&W film that is used for creative purposes as images will show a sharp shift in tonal values, esp. in bright sunny weather when objects transmit & reflect a lot of infrared light such as healthy foliage, which then record almost white & luminous. In contrast, open blue skies & bodies of water that reflect little IR, are printed very dark which can create stunning contrasts with clouds. Portraits can be interesting as it causes skin tones to look bleached, may expose veins, whereas eyes look dark & brooding, allowing a dramatic or spooky or more magical effect.
IR film also cuts through haze in distant landscapes & can also be used at night in the dark if there is a IR lightsource.
see comparison of films
here
IR films:
Kodak HIE:
discontinued Dec 2007.
the most sensitive (to 900nm, peak 750-840nm) & provides the most spectacular results
low sensitivity to green; fine grain & very sharp;
no anti-halation layer & must be loaded in total darkness;
the dimpled pressure plate of Olympus OM cameras is only a problem with 87 or deeper filters, and only on bright scenes.
good IR effects even with Wratten 25:
relatively expensive and unfortunately not available in 120 format
although gives the best Woods IR effect, it tends to lose highlight detail in high contrast scenes more than the other films, and is much more grainy (the other films have similar grain to Kodak TMax 400)
Unfortunately Kodak is discontinuing manufacture of this unique film in Dec 2007, so Kodak HIE will be no more - see
link
Efke IR820c
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Croatian film manufacturer Efke uses same recipe as for Maco IR820c to make this film
need IR filter for Wood's effect (25A red filter will not give IR effect as with Kodak HIE film)
fine-grained, sharp;
“very high” sensitivity up to 820nm then sensitivity rapidly falls and cuts off at 850nm and thus the manufacturer does NOT recommend extreme filters such as #87B
1);
closest rival to HIE but 2 stops slower;
135 film should be loaded in total darkness;
120 film size available can be loaded in very subdued light.
for each series of bracketed exposures, shoot one frame without a filter exposed at ISO 100 to help address processing issues
has an anti-halation layer (processed out during development leaving a clear base);
AURA version gives halo effect.
can use TTL metering set at ISO100 if using yellow, orange or red filters but not if using infrared filters.
if using a handheld lightmeter, set to ISO12-25 when using a 25A filter and ISO 1-6 if using an IR filter.
reciprocity failure: double exposure at 4secs; triple exposure at 8 secs; results will be more contrasty with deeper shadows.
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Rollei 400 / Rollei IR 820:
peak sensitivity at 670nm then drops rapidly to 820nm
fine grained; sharp; suitable for scanning;
135 film should be loaded in total darkness;
120 film size available can be loaded in very subdued light.
film should be kept below 8degC if possible and developed
ASAP after exposure.
halo / aura effect by over-exposure.
similar to Maco IR820c but rated at ISO 400 without filters.
yellow (#8) then rate at ISO 200-320
dark yellow (#15) then rate at ISO 200
yellow/green (#11) or orange (#21) then rate at ISO 100-200
red(#25), RG 715 (Heliopan) or Kodak #88A IR filters, then rate at ISO 25
Hoya R72, try ISO 12 (but this will over-expose sunlit skin)
RG 780 or #87C and higher not recommended as no image will be obtained
only mild IR effect with 25A red filter - blue sky is rendered as mid-grey.
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Konica IR 750:
slower, very fine grain; speak sensitivity 700 to 740nm with minimal semsitivity beyond 750nm; not sensitive to green;
easy to handle as has an anti-halation layer & can be loaded in subdued light
lovely tonal rendition with Wratten 25 (effective ISO ~6) but needs 89B (effective ISO = 3-8) for best IR effects;
use ISO 3 with Hoya R72 filter and ISO 1.5 with #88A filter;
stocks only produced once a year around April.
maybe available in 120 film size;
spectral curves have two peaks:
Ilford SFX 200:
not a true IR film, and the least sensitive of the four, only to 740nm (peak 720nm); easy to handle as has an anti-halation layer & can be loaded in subdued light
large grained, great for dramatic high-contrast effects only; latitude +1 to -1 stops
need Wratten 89B or Ilford's own SFX filter to give good IR results
Kodak Ektachrome color IR film:
has 3 layers:
precautions using IR film:
most must be loaded into camera in complete darkness as its lack of anti-halation layer which normally prevents flare from bright lights, in addition to giving the film its wonderful glowiness in the highlights, makes it extremely sensitive to fogging by stray light.
must be loaded into a IR-safe processing tank (eg. Paterson tank) in complete darkness
should be stored in its original container in the fridge or freezer until ready to use then defrosted to room temperature before opening to avoid condensation
must be stored lower than 55degF if possible as high temps will cause fogging - ie. a cool place ⇒ NOT in the car!
to keep out visible light which would take away its effects, must use a red filter such as Hoya 25A (Wratten 25) - can use a deeper filter such as Hoya R72 (Wratten 89B) but this appears opaque and one can not focus or compose through it, and thus it must be applied just prior to taking the photo.
there is no ISO rating like normal films, so have to bracket exposures +/- 2 stops in 1 stop increments, try using the following for Kodak HIE film with Hoya 25A filter:
bright sunshine in warm summer conditions: set ISO to 400 & use TTL meter as a starting point
cooler but bright sunny days in spring/autumn: set ISO to 200
cooler, overcast day: set ISO 100
focusing issues:
IR focuses slightly closer than visible light which is an issue with simple lenses and achromatic lenses but not a real problem on apochromatic lenses or pure mirror lenses.
on many SLR lenses, there is a red marker to indicate IR focus
it usually is not a problem if there is sufficient depth of field such as when using a wide angle lens for a landscape.
beware that stopping down a lens to create depth of field may make things worse as the diffraction limits are much worse for IR and thus you need to use a larger aperture to avoid this (eg. f/8 is normally the smallest aperture on prosumer digitals due to diffraction issues, for IR, you may need to settle with f/5.6 or 6.3 being the smallest aperture).
processing IR film:
printing IR film:
make a contact strip and look for frames where black of scene matches the black of the film base with a density roughly equivalent to normal negatives
remember to allow highlight areas to glow & sparkle
dense HIE negatives show a rapid increase in grain and reduced tonal separation and will interpret ghostly, grainy & dramatic.
experiment with the different moods.
IR photography with digital cameras:
summary of what you need:
most digital cameras have a CCD sensitive to near IR light up to ~1100nm, but also have a special IR-blocking filter in front of the CCD as the IR light would otherwise degrade the image, thus sensitivity ranges are usually:
normal digital cameras with IR & UV blocking filter: 400nm to 750nm
normal digital camera with IR & UV blocking filter removed: 280nm to 1200nm, but because CCD sensitivity is reduced at the extremes, the practical range is approximately 325nm to 1100nm.
the best time to shoot IR is either in the late morning or early evening. When the sun is directly overhead, it is hard to get good contrast between IR sensitive objects and the sky.
focusing:
ideally, the live preview on your camera will display sufficient detail with your IR filter on so that you can manually focus
if your camera will not focus with your IR filter in place, then consider using a old manual focus lens with IR marker, then without the IR filter focus then adjust focus to the IR marker then replace the IR filter.
IR-pass filters which must be used:
exposure:
digital cameras have the advantage that their auto-exposure & auto-focus should still work BUT be aware that the camera will try to adjust exposure so that average of all 3 RGB channels is correctly exposed, BUT THIS IS NOT WHAT WE WANT as the main channel we are interested in, the red channel will be grossly over-exposed, so you need to set exposure compensation perhaps to -1 to 2 EV. You will not be able to rely on the camera's histogram either unless it shows the 3 RGB channels rather than the resulting jpeg image histogram. Thus your exposure will need a bit of trial and error comparing your red channel results with your camera exposure compensation setting.
monochrome images:
ideally one should shoot in RAW mode, then in Photoshop, select the red channel and convert to monochrome then adjust the levels to improve the contrast.
some cameras allow in-camera generation of monochrome images by selecting Black and White option but this will use all 3 RGB channels which is not what we want.
color IR images:
colour IR is not easy to achieve on cameras with high IR blockade, while they are possible on the Sony F7x7 with a R72 filter, the Sony F828 appears to give better colour IR is one uses a deep red 29 filter instead.
try setting WB to manual and metering with filter on for interesting colour effects - sepia-like
or, take 2 identical photos, 1 with the filter and 1 without the filter but exposed normally but at same aperture to ensure consistent depth of field
post-processing method 1:
selecting the color image, selecting the entire image (ctl-A), clicking on the “Channels” tab and selecting the green channel and copying this (ctl-C), selecting the blue channel and pasting (ctl-V). Repeat the process to copy the red channel into the green channel. Select the IR image, select the entire image, copy the red channel, return to the color picture and paste it into the red channel.
this may produce “crazy” colors
post-processing method 2:
post-processing a Sony green nightshot image with R72 filter on:
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create duplicate layer
open hue/saturation and set green saturation to minus 100%
then change master to: hue = +124 and saturation = +50 to 60
use Gaussian blur of 3-5 pixels radius on background copy layer to reduce noise
change background copy layer to layer method “colour”
use auto-levels on background layer
open hue/saturation on background layer & set red saturation to minus 100%
flatten the layers
post-processing via
Daniella (“zylen)” method using a Dimage 7:
take a good photograph with good subject, white balance to tungsten, color saturation to -3 or -2 and contrast to -2.
copy the layer and apply auto-level. Adjust the slider to adjust the result. Once the result is ok, merge them.
copy the layer again, then adjustment, channel mixer and swap the blue and red channel. Keep the unswapped image underneath. You can add a layer mask and blend the swapped and unswapped image, and reveal or hide part of the swapped image that you want or don't want.
create a new layer and use “color” mode for the blend. Then use the color that you want and spray the area to tint the area that you want to correct.
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take a photograph using custom WB on sunlit grass through the R72 filter
Image > Adjustments > Channel mixer:
Image > Adjustments > Hue and Saturation
From the drop down menu choose Reds and desaturate to minus 100
From the drop down menu choose Magentas and desaturate to minus 100
If the pic is dark choose Blues from the drop down menu and adjust lightness to plus 70 or to your taste
If your photograph is overexposed all the overexposed areas will show up as yellow.
In this case you will then also choose Yellows from the drop down menu and desaturate to minus 100 or according to your taste
While in yellow also adjust the lightness slider to the positive side till you achieve the desired brightness
When done click OK
Photoshop actions for digital IR post-processing:
cameras that have fixed IR-blocking filters:
very weak IR blocking allowing full sun exposures approx. 1/8 to 1/2 sec for f/4 at 100ISO:
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Canon S30
Leica M8:
expensive and although IR is possible, focusing is problematic
approx. 1/30th sec, f/2.8, 100 ISO
in fact, for non-IR fashion photography, Leica recommends a special IR/UV blocking front filter be used.
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Weak IR blocking allowing full sun exposures approx. 1-2 sec for f/4 at 100ISO:
Medium IR blocking allowing full sun exposures approx. 3-5 sec for f/4 at 100ISO:
Olympus C8080WZ landscape with Hoya R72 filter f/2.8, 50ISO, 1.5-3secs but central bright spot at wide angle
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Strong IR blocking requiring 15sec exposures in full sun at f/4, 100ISO:
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Canon 1D Mark III - 3200ISO, f/1.8, 1/15th sec at EV 14 (sunlit with some high cloud) but very difficult to use the Live Preview for IR, unlike the Olympus E510.
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Nikon D70 landscape with RG9 filter f/13, 800ISO, 1/2 sec;
Canon 10D landscape with RG9 filter f/13, 800ISO, 8sec;
Canon S30 with handheld R72 filter, 400ISO, f/3.2, 1/15thsec, RAW with desaturation and histogram levels adjusted:
eg:

cameras that do not have a IR-blocking filter:
cameras that have a non-IR-blocking mode:
some cameras allow you to remove the IR blocking filter, but as this allows one to take “see-through” photos through dark clothing, the manufacturers such as Sony prevent this from being used in daylight
Sony nightshot mode:
Nightshot IR pictures are taken by setting the dial on the cam to Auto and the Nightshot switch to “Nightshot”. The aperture will be forced to open all the way up (F2 to F2.4), and fastest shutter speed will be limited 1/60th sec with a 7*7 or 1/30th with a V1 or 828. You will most likely need one or more ND filters to darken the scene plus your IR filter, as the pictures will be overexposed otherwise. In nightshot, the IR hot mirror is removed from in front of the CCD, and the camera will be very sensitive to IR light. These pictures can be taken handheld, and come out looking green.
Another good thing to have when shooting in Nightshot is a donut cover for the IR emitters. These are the two little holes that are around the lens near the top. If you don't cover these, you will get a round circular reflection near the top of your pictures from the IR light reflecting off of your filter. You can make a donut out of cardboard and cut the outside diameter by using my lens cover, and the inside diameter adjusted until it was just outside of the lens. Pop the donut on and then stick your IR filter on over the top. (not required on the F828).
may need to set EV from 0 to -2 and ISO to lowest setting (64-100) - DON'T use auto-ISO!
filter options:
if you shoot with “Daylight” WB, your pictures come out with a Reddish tint. With “Indoor”, you will get a purplish tint. If you use the “Manual WB” button. This will make the foliage green and the sky reddish.
in Nightshot mode, the camera’s metering pattern is center-weighted averaging.
other features that still work when in Nightshot mode:
modified cameras with IR blocking filter removed:
Portrait photography with IR:
IR can almost totally eliminate many complexion problems—even acne pockmarks—as long as your subject is evenly frontlit. Infrared film, when exposed through a red filter and printed high-key (in other words, light) on a contrasty black-and-white enlarging paper (as in the portrait, left), will reproduce Caucasian skin tones in creamy, almost ghostly whites. Pimples and other surface imperfections simply disappear.
A black-and-white film that's sensitive to visible light plus the 750–840nm wavelengths of infrared radiation, HIE is easier to learn to use and, at $12 per 36-exposure roll, is a fraction of the cost of Adobe Photoshop. The film is very grainy, especially when overexposed, so meter carefully and don't plan on making wall-spanning enlargements. The lighter and more contrasty you print it, the less objectionable the grain becomes. Unless you have a darkroom, you'll probably need a custom lab for the film processing and printing.
Correctly exposing infrared film isn't your only challenge. Because camera lenses don't focus infrared radiation in the same plane as visible light, for maximum sharpness, first focus normally, then shift focus slightly toward infinity. Many lenses indicate the degree of shift with a tiny index mark on the focusing scale. One last thought: You'll need to use a deep red Wratten #25 filter to block red (i.e., blemish-colored) light from reaching and overexposing the film.
Test infrared film under your shooting conditions to explore its idiosyncrasies. You may need several test shoots, altering the lighting, exposure, and printing.
Infrared film responds differently depending on the light source. Whenever you change lighting, retest.
While the effects are not as dramatic, try Ilford's near-infrared film, SFX 200. It's easier to use and less expensive than HIE.
If the complexion problem is minor, any black-and-white film (or monochrome mode in digital) shot through a red filter may mask the skin condition.
Some 35mm SLRs' film advance systems use film-fogging infrared light beams. Check your camera manual.
Various Photoshop post-processing techniques for digital IR photos:
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1.[ image]→[Adjustment]→then[Hue/Saturation]
2. Select [Green] From the dropdown menu, adjust the [saturation] to -100
3. Select [Master] From the dropdown menu,
4. Adjust [saturation] to +50 & adjust [Hue] to +120
5. [image]→[Adjustment]→then [Brightness/Contrast]
6. Adjust Contrast to +15
7. Finally, do the [Auto Level]
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using Nightshot mode on a 707.
IIRC, the filters were Hoya r72, ND8 and polarizer. Post processing is seat of the pants type. Generally, with IR, I use PSP's Hue/Saturation/Light filter to desaturate, then apply contrast filter. I frequently then use PSP's Clarify filter, which is a special contrast filter, sometimes applying it twice. Then I use unsharp mask and apply a color tone using HSL.
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Lou Gonzalez:
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When the images come out of your camera, they will have a dark green cast.
1. Go to Image / Adjustments / Levels to boost brightness/darkness (use right most and left most sliders).
2. The go to Image / Adjustments / Channel Mixer, check Monochrome, then use the specific RGB channels to boost certain characteristics of the image.
3. Then do Image / Adjustments / Auto Contrast to add more punch. Or adjust Contrast to you liking using curves or other technique.
For the colorized IR shots below, I used the following method:
1. Image / Adjustments / Levels.
2. Image / Adjustments / Hue/Saturation.
3. Select Green From the dropdown menu, adjust the Saturation to -100.
4. Select Master From the dropdown menu.
5. Adjust Saturation to +50 & adjust Hue to +130 (for blue effect) or -60 (for red effect), or customize to taste.
6. Adjust Contrast (optional).
7. Finally, do the [Auto Level].
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Take two images, one color, one IR.
In PS copy the IR and paste it as a second layer on top of the color version.
Level the IR layer to become close to B&W.
Set the blending mode to luminosity.
Thermography:
thermography uses special infra-red cameras to image & measure radiant heat from objects
cameras typically measure temperature ranges of minus 20deg C to 300 deg C with resolution of 0.1degC, although some will measure up to 900degC or more.
whereas digital cameras usually only detect 0.4 to 1 micron wavelengths, thermal cameras that detect heat use a different sensor technology (Microbolometer Uncooled Focal Plane Array (MUFPA)) and fall into two main groups:
can show areas of a house where heat is being lost or the different skin temperatures on a person
most only have resolution of 320×240 pixels
US law means that these cameras cannot be sold to non-US citizens apparently
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photo/infrared.txt · Last modified: 2018/08/22 09:57 by gary1