Free Photoshop Tutorials: Adobe Photoshop Lightroom – How to remove color noise

1. Load the photo
Everything cannot be perfect. A lens may not be perfect either. These may cause color noise — or by its beautiful name of chromatic aberration — among others. You will most often spot them on the edge and in the corner of photos in the form of purple-green or blue-yellow color stripes. In size it can vary from tolerable to absolutely disturbing.

This problem is quite conspicuous on the 100% magnification of the picture detail above, but if it’s not big enough, we have put an even bigger version to the left. It’s a piece of cake to remove these from RAW images if you know what to use in Lightroom.

2. Where is it hiding?
Well, use Develop section and within that visit Details part in the setting panel on the right. Chromatic Aberration window is here with a few sliders and a small menu.

The first thing to do is to identify the color of the aberration in the photo. In our case it’s a purple-green discoloration, visible especially at the edge of the areas with big contrast difference. Therefore we begin with Red/Cyan slider.

3. Red/Cyan
If you raise Red/Cyan slider value, you will get an even stronger color distortion, so we have to decrease it carefully, until the noise is removed. You may want to use a 100% or even higher zoom value to be able to observe the noise.

We decreased Red/Cyan value gradually — in grades of five — and arrived at an acceptable result with the value of -25. But, as you can see above, there’s a little blue-yellow noise left.

4. Blue/yellow
To remove the weak blue-yellow aberration, we used Blue/Yellow slider of course. This time we shifted it in the positive direction. A value of +10 proved to be sufficient to remove almost all of the discoloration.

5. Alongside the edges
Slight versions of purple color noise, called fringe, can be removed with the help of Defringe menu under the sliders. This menu comes handy after we have finished modifications on the sliders and wish to further refine the result. There is some purple discoloration alongside some of the edges still, which can be removed completely by selecting All Edges menu. This menu can help decrease the slight purple color stripes on the dark and light side of edges. Highlight Edges will remove noise from the light parts of edges. Slight color aberration will usually appear on light parts.

6. Free of color noise
The left side shows the original state with the quite conspicuous purple-green color noise, while the right side shows the result of our brief actions, practically free of color noise.