First you have to decide if you want to do colour or b/w.
If you want to get colour images , use a 630 up to 720 filter, the filters below this wavelenght (750…950) will give you nearly no colour information…
Different sensors or films give remarkable different results!
The Standard IR Filter (720nm) is the classic IR filter. It allows some visible light to pass for color processing and gives good contrast for black and white. E.A: the Hoya R72 and Wratten 89b.
The 550nm IR Filter lets in the lots of visible light creating blue skies and blood crimson reds. It has the look of old IR films. It’s also good for infrared portraits, it keeps rather neutral skin tones (the 590nm will expose veins) and still provides color information.
The 665nm filter is in between the 720nm and the 590nm, showing more vibrant colors than the 720nm. The 665 comes out more reliably between different cameras and lighting conditions.
The 850nm filter and 920nm are good for black and white IR and will show bright whites and pronounced darks. With a custom white balance in camera, the picture is close to pure B+W. E.a. the Wratten 87c.
With film test your focus and your exposure time with bracketing, both can be rather difficult to find and change rapidly and sometimes unpredictable with light conditions (we cannot see infrared;-) ).
Try to have the sun in the back or at your side, pics toward the sun often have very low contrast and lots of flares.
Best are sunny days and the trees and grasses should be green to get the „wood“ effect.
The best light source is the sun, but moonlight works well, too.
Camera flashes emit infrared as well as visible light so they can be used for infrared flash photography. It is possible to cover the flash with an IR filter to get rid of the visible portion of the flash and have a dedicated IR flash.
If you go digital:
Use raw files!
Use a modded camera with no infrared filter (or give it a try with a tripod and take your (long) time)
Use „live view“ if possible, so you should be able to rely on the automatic metering and autofocus.
In your raw converter:
If you shoot b/w use the LAB modus and the L (red) channel.
For colour
Set your white balance on the (white) greens
Use the cannel mixer to switch the red and blue channel.
(This is the usual result:
Red Channel: Red=0, Green=0, Blue=100
Blue Channel: Red=100, Green=0, Blue=0
Green Channel: Red=0, Green=100, Blue=0
Sometimes this is giving a better result:
Red Channel: Red=0, Green=0, Blue=100
Blue Channel: Red=100, Green=100, Blue=-100
Green Channel: Red=0, Green=0, Blue=100
Add Hue/Saturation
Apply contrast / use curves / dynamic contrast…
Add structure/details/clarity or however your software names it
Play with blending modes (contrast etc, e.a. luminosity)
Small variations in my White Balance or Channel Mixer settings (the two most important settings for IR) as well as the sequencing of the processing steps have often led to very different results.
Your IR results will depend on several more factors:
- Camera make/model and sensor
- Infrared filter used (there may be even variations between vendors)
- RAW or JPEG processing
- Your Lens
- Type of vegetation and its ability to reflect IR light
Still for me to try:
Vittorio Sergi : If you like the usual 720nm faux color conversion with a blue sky, just skip the channel swapping step altoghether, grab a hue and saturation Adj. layer and slam the hue slider one all the way left or right so that the value reads 180 or -180, there you have a nicely done blue hue as it should be, given that you nailed white balance
720nm Filter, May 2020:
https://photographylife.com/infrared-photography-720nm-filter
https://www.lomography.com/magazine/320088-6-infrared-films-for-that-otherworldly-glow
https://www.scottdavenportphoto.com/blog/how-to-process-an-infrared-photo-in-on1-photo-raw-2020