Photographer Mark Wood is from North Staffordshire and shares his knowledge of photography through teaching and writing. Mark has shares his techniques for Infrared Photography using the SIGMA SD1 Merrill and Sigma Photo Pro software. 
The world of the infrared is just beyond sight. It is an exciting space to navigate. Like the days of film, chemistry, and darkrooms there is something of the arts of alchemy in digital infrared photography.
The reward for the patience needed to make digital infrared work are photographs that appear ethereal, and to a degree ambiguous, because their tones and clarity are beyond those normally found in monochrome photographs.
I prefer to use the word monochrome, because almost no photography is purely black and white. All the photographs here are full of tone, they have also been tinted with a light sepia to add warmth.
Monochrome, tone, tint, and infrared are all terms with specific meaning here. Let me explain what I mean by infrared photography. These photographs are not digital trickery, a faux effect applied in post-processing. I use a camera that can record the invisible light found beyond the red colours of the visual electromagnetic spectrum.

Infrared extends from 740nm to microwaves at 1mm. Without diving in too deeply into Physics, these photographs are recorded in the Near Infrared and include some reds from the visible spectrum. I have been using a Kood R72 Infrared filter, which only allows light from 720nm and longer to enter. Infrared (IR) filters are available in a range from 650nm to 1000nm.
The extent to which digital cameras can record infrared energy varies. As we can not see infrared, or ultraviolet (UV), camera manufacturers try to block this invisible light from falling into the camera sensor. The common method for blocking IR and UV is adding a filter to a camera’s sensor. Infrared photography can be impossible with the IR/UV filter in place. Removing it is a specialist job, that is irreversible, though not on the Sigma camera I use.

Removing the IR/UV filter in several models of Sigma camera is a simple process. Photographers just need to slide the filter in the direction of the arrow embossed on the filter, then carefully lift the filter from the camera. Replacing it is as simple, making these Sigma cameras ideal tools from infrared work.
The key ingredient for infrared landscape work is strong sunlight. Photography on grey days does not yield work that reveals any infrared characteristics.
In woodland, infrared photography causes foliage to turn to white or light greys; blue skies to black, or dark greys.

When the sky is blue, IR photography reveals itself. Skies can become black.
Processing infrared photographs from my Sigma SD1 Merrill is a three step process. The raw shots need to be passed through Sigma’s PhotoPro software; here I shape the tones, apply lens correction, but leave the photographs in RGB colour, and save the files as 16-bit TIFF images.

i batch-process the Sigma TIFFs by opening groups of photographs in Adobe Camera Raw (ACR); sometimes I import the TIFFs into Adobe Lightroom, which gives me the same facility as ACR to make a monochrome mix and apply Curve adjustments in a non-destructive way.


 
 
 
 
 

The four screen grabs show from left to right. 1. Some of the minimal adjustments I make in Sigma PhotoPro. 2. Curves in Photoshop: I apply Curves in ACR too. 3. The flat looking monochrome landscape before the sky is darkened using a Curve Adjustment Layer with a gradient mask. When I teach these processes I take time to explain more fully. 4. The final image, an RGB photograph with light sepia tone applied, note the additional depth of tone given to the sky, when compared the figure 3.
I believe that robust post-processing of infrared digital photographs is need to make such images have any visual appeal. Even correctly exposed infrared shots need careful processing.
Not all my infrared work has been about landscapes. The macro-world has led to fascinating images of flowers.

The tonal richness of these monochrome photographs is enhanced because greens become whites in infrared.
The delicate paper-like quality of this photograph demands further study, though to my eternal frustration time is at a premium in our fast moving world.
In landscapes, shooting in the infrared cuts through atmospheric haze. This makes distance objects clear and crisp. From foreground to horizon the additional clarity of infrared shines through.

My journey through the infrared world has barely begun. Exploring false colour, and a hundred other landscapes beckon.
To find out about the tuition I offer please visit
Mark Wood | Photography
All the best for your journey, wherever it takes you…
Credits:
All photographs and illustrations by Mark Wood ©markwoodphotography.com 2017