Words and images by David Clapp - www.davidclapp.co.uk
After purchasing or converting a camera to Infrared, the problems with processing can cause a lot of head scratching. To start with, the images tend to look intense, garish and 'completely wrong' to say the least. I too have struggled to find my way in this strange world, so here are my findings and my workflow. It's not surprising it is complicated as infrared is an interpretive medium. There is almost no 'right and wrong', but there is a balance and that is what I will explain below.
Infrared Camera Settings
What are the right settings to use for image capture? Well auto settings are no help here. Shoot RAW, shoot in Manual Mode and shoot manual focus lenses. Many if not most AF lenses create a light 'hotspot' in the centre of the image, created by the infrared light emitted by the camera. It can be post processed out, but it takes time, so I use the adapted Contax 35-70 when shooting IR.
When approaching the computer, the biggest problems occur with white balance. Auto white balance will cause all manner of issues and inconsistencies, making intense poppy-red looking files that are nothing like the one subtle result above. To avoid this problem, set the white balance to a custom setting, using the K white balance setting and push this as far back as possible. I used a minimum value of 2800k to reduce the intense reds. This will make the images look purple (I know, I know), but it's the most pleasing place to start and further adjustments will naturally be made in RAW.
Adjustments in Lightroom
This is how the images look directly out of the camera. There is a very intense magenta cast, but the intense reds are gone, making the image taking experience seem positive rather than a world of utter confusion.
The next thing to do is to balance the shot so the grasses and foliage look white. Rather than endless manual play with the TEMP and TINT sliders, the easiest thing to do is use the eye dropper, yes you know, the one that's totally useless when working with any other type of image.
Grab the eye dropper tool and click on the foliage or grass and bingo, everything starts to look balanced.
Try making a few clicks with the eye dropper in various spots on the image and see if the balance is more to your liking. Further adjustments to the TINT and TEMP sliders can help further. Place the dropper on the grass or the foliage and these will turn white. Now we are getting somewhere.
Once balanced begin to work the image is worked in the usual way, improving contrast by making adjustments to exposure, blacks, clarity and curves. Now convert to a TIF and open in Photoshop.
False Colour Infrared
To create that weird but compelling blue sky effect that many infrared images have, simply use the Channel Mixer to 'swap' the values in the Red and Blue channels.
Examine the Red Channel. It contains three sliders with Red = 100% Green = 0% and Blue = 0%. You guessed it, the other channels only have 100% values on their own colours.
The secret is to swap the reds and blues around, so in other words the RED channel's values are Red 0% Green 0% and Blue 100%.
Now reverse this for the Blue channel - Red 100% Green 0% and Blue 0%. Here are some snapshots showing the channel mixer settings for each separate channel.
When Does It Work?
So here is the end result, blue sky and blue water. It looks rather wonderful and very relieving to see some sense of normality about an IR image. This is why channel swapping is so popular, but when does it work effectively and why does it often have little effect?
Remember, the infrared camera is capturing subtle blues as reds, so an image that doesn't contain blue sky, water reflections etc. will not respond well with this channel swapping. In fact, it will probably have little or no effect, so make sure the sky is clear or there are clear gaps for the swap to work. Even though your eyes can see blue, high cloud will ruin the chances of a good conversion significantly. The deeper the blues at the point of capture, the better the swap will be.
A Few Words About Infrared In Black And White
Black and white is probably the most acceptable medium for infrared (and by far the easiest to start with) as it is a readily accepted representation. The eye finds the tonal differences rather compelling and more acceptable than the colour concept, which is often a little 'psychedelic' for many.
Here's the same IR shot modified once again using the Black and White Filter. The red channel is naturally the most sensitive, but yellow and magenta also add masses of tonal control. Make sure to explore the image at 100% as the B&W Filter can be very aggressive, introducing noise in the shadows and skies.
Finally, for those of you who were wondering, the image was taken at a lake called Tecwyn Isaf in Snowdonia. Wonderful isn't it!