7. Although you’d normally want to minimise image noise, some infrared photographers like noise because it emulates the grain of infrared film. To add this effect, select Noise, Add Noise from the Effects menu. Now adjust the controls until you get the desired effect and click ok.
8. To add colour to an infrared shot, you can combine an infrared photograph (with the filter in place) with one taken normally. The shots must match perfectly, so use a tripod and don’t move it between exposures. Use aperture priority or manual exposure so the aperture is the same. Ideally, you should shoot RAW or Tiff images.
9. Our first colour technique duplicates Kodak’s Infrared Ektachrome film, which reproduces infrared as red, red as green and green as blue. Open the normal image and select Image, Split Channels to, RGB. Three new images will appear, showing the red, green and blue content of the original image respectively.
10. We’re not going to use the blue image, so close it without saving. Now open the matching infrared photograph. Convert it to monochrome and adjust the contrast as you did in steps 5 and 6. Next, we can combine the infrared, red and green images into a false-colour photograph.
11. Select Image, Combine Channels and choose RGB as the mode in the Combine dialog box. Select R as the channel and browse to your infrared image in the image list. Then choose G as the channel and the red picture from the list. Finally select B as the channel and the green image. Click ok, and you’re done.