Saturday, December 3, 2016

Inverting an Infrared Image to Produce a Different Look

Sometimes you want to change the look of a photograph or just try something new. Inverting the image is an interesting way to do that, especially if you want a high contrast final image. For this post, I am going to start with an infrared photograph of Christmas tree ornaments taken with a Nikon D90 with a supercolor (590nm) conversion. 
Click for larger image
Figure 1. Original IR image.

This image was taken at Matthaei Botanical Gardens in Ann Arbor, Michigan. They had a number of trees in the greenhouse that were decorated by various businesses. This tree had some interesting wooden spoons that looked like people.

The original image was interesting, but it had relatively low contrast and the overall feeling was 'meh.'  I wanted to add a bit more drama to the image. Hence, the inversion process.

A simple inversion of this image using Layer > Adjustments > Invert or a simple inversion adjustment layer (my preference), would give you a blue image that looks like this (Figure 2).
Figure 2. Simple inversion of the original image

While that might be an interesting starting point for some images, my goal was is to create a contrasty black and white image. To do that, I used two adjustment layers - a black and white adjustment layer and an invert layer. 

More specifically, I 
1.  Hit CTRL-J (CMD-J for a Mac) to duplicate the background then I turned off the original layer
2.  Added the BW adjustment layer
3.  Added the Invert adjustment layer

The layer stack is shown in Figure 3.
Figure 3 . Layer stack for inversion.

At this point, the image will look a little strange but much of that can be ironed out by returning to the Black and White adjustment layer and moving the sliders to get an image that looks more like a film negative.  

From there it's a matter of giving the image more contrast and cleaning up some of the ugly bits that occur during the inversion process.  

For example, I used a white brush on the spoon in layer 1 to make the spoon uniformly dark and I used the same technique to even out the inverted hotspot on the bulb ornament.

After that, I used normal processing techniques to address brightness, contrast, levels, etc. and to make the image reflect my artistic aesthetic

The final image is shown in Figure 4.
Figure 4. Final Inverted image.

Please let me know if you found this post helpful..

Happy IR processing!

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