White Balance (WB) is adjusted during the shooting process or in RAW-converter, and you may get the next variants of images.
Left upper image is converted from RAW-converter without WB adjusting. On the right upper image WB was set on the leaves in RAW-converter. Two other photos are combined with two upper photos with the help of channels changing.1. First, open your image in Photoshop and study the channels. As a rule, brightness is kept in the red channel, sharpness - in the green channel and noise - in the blue one, but of course different variants are possible.
the original infrared image and the edited one
2. After that you can apply Auto Levels option to the image. Image -> Adjustments -> Auto levels or Shift+Ctrl+L
3. Then, go to Image -> Levels (or Ctrl+L) and move the histogram sliders, achieving the acceptable tonal range. Also use the white point picker to point the areas that you know are white, for example clouds.
4. The next step is Channel Mixer. Here you should make the replacement for Red and Blue Channels. It means you choose the Red channel and set 0% for red color and 100% for blue color. Than you go to the Blue channel and set 0% for blue color and 100% for red color.
5. Then we apply Shadow/Highlight to align the tonal range of the image with the settings on the picture. But don't go too far with that, otherwise your image will look unnatural. It's recommended to put Radius about 250-350 px.
If you are not satisfied with the result, you can still change the sliders position in Channel Mixer, until you find the required colors.
Infrared Post Processing Tips:
- Due to the long shutter speed the Red Channel appears to be very noisy. You can adjust the sky color to become clearer.
a. Open your image in the 100% scale.
b. Add an adjustment layer Hue/Saturation.
c. Move the slider to the right (to the blue color), searching the value, when the noise is less visible (Hue is about +15 to +24).
- You also can work with Saturation in any way to change your image as you like.
- If you increase Sharpness your image will be effective.
Black&White IR Image Editing
I. There's also an easy way to get a black and white photo. After Levels adjustment, go to Channel Mixer and change the settings, having ticked the Monochrome option. After that you can tint your image according to your needs, using any possible method .
II. The second way is a bit more complicated and is mostly used with the shots in the RAW format. Here's what you need to do:
1. Convert your photo in the RAW-converter, not forgetting about the white balance setting. Point any green leaf with a white picker.
2. Then go to Image -> Levels (ctrl+L), change the histogram, achieving the acceptable tonal range.
3. Transfer your photo in the LAB profile and combine the channels in the Apply Image box just as you like.
4. Get back to the RGB profile and carry out the final editing by the Levels and Shadow/Highlight tools.