As we near the completion of our image processing, one of the final steps is to make final color adjustments to the structure and the stars.

Note: The remainder of the adjustments are minimal.

Color Saturation

We might wish to add an additional level of color saturation to our image without changing the background. To do this, we need a mask. This time, I use a range mask:

I try to limit the lower limit so that I am mostly able to focus on the bright core of the object, but I need to not go so high that I have a sharp break into areas with lower signal.

I set the fuzziness at maximum because I want the textured details in the higher signal areas. I find when adjusting saturation, this provides a more dynamic result.

Once this mask gets applied with the background protected, we can use Curves Transformation to gently increase the saturation.

I typically apply this multiple times until I reach the color intensity I’m looking for.

First Color Saturation
Third Color Saturation
Second Color Saturation
Fourth Color Saturation

This becomes a personal preference. But for me, I’ll stick with the third color saturation example as I feel in this image, the fourth one was too much.

Star Color Adjustments

The next thing I want to adjust is the star color. Most stars are not white, yet the ones in the image take on a predominately white tint. To focus our attention on the stars, we apply the Star Mask. The following provides details on how to create a good PixInsight Star Mask or Using StarNet to Create a Star Mask.

With the star mask applied to our image, it should protect everything but the stars.

With star color, I take apply a slightly heavier application of saturation to achieve the star color I’m looking for.

Note: To get realistic star colors with narrowband imaging, you need to capture through Red, Green and Blue filters and use those star colors to set the hue for the narrowband star colors.

What’s Next

These color adjustments were minor, but they do improve the overall image.

Before Final Color Adjustments
After Final Color Adjustments

The next step is to do do a final adjustment on the brightness of the image and background.