Integrating our individual channels into a single image is a great accomplishment. Unfortunately, the outcome will be far from ideal. Most likely, one color will dominate the image and making it look like the integration was a failure.

This is where color calibration comes in. It allows us to better balance the colors so we get an image much more pleasing to the eye.

Auto Color Script

One of the easiest ways to fix the color balance is with the Auto Color script (Script – Utilities – AutoColor)

There are no settings to apply, it just executes on the currently selected image.

After Auto Color Script

The script did a nice job lowering the green intensity and helping out with the overall background.

To further reduce the green tint, we move on to SCNR

SCNR

NOTE: Although I placed SCNR here, I’ve since realized that SCNR works better in non-linear mode. Take a look at the SCNR page to see the subtle differences between doing it in linear vs non-linear.

The SCNR is the Subtractive Chromatic Noise Reduction. Basically, it will remove a color from our image without reducing the overall brightness.

After SCNR

This makes a huge difference in the image, but I need to take are of the magenta stars as this is an uncommon color for astro photos. What is wonderful about magenta is that it is opposite from green on the color wheel. This means we can invert our image and run SCNR again

Inverted Image
Corrected Image

What’s Next

Color correction made a big improvement to the image

Before
After

With the colors calibrated, our next step is to work on the color saturation.