By Anna Gay on | No Comments
Have you ever noticed how, in some of your shots, your subject and or certain elements of the image will have a colored halo around the edges? This is known as "Chromatic Abberation" or sometimes called "Color Fringing." In this post, we will look at what it is, and how to correct it in Photoshop.
I don't want to get too bogged down in lens optics in this post, because this post is geared more towards correcting the problem than analyzing it, however, it is important to know that chromatic aberration can occur with any type of lens. It is the result of our lenses failing to focus on, and line up, various colors as they enter our lens.
Some of the most common color fringes are magenta/red, and cyan/green. So, for example, when you see a magenta halo on your subject, you will know that the color magenta did not hit the convergence point in your lens with the rest of the colors on the spectrum, therefore it is visible in your image.
Color fringing is most likely to occur in high contrast images, so you will often see color fringing in images that are backlit.
It is quite common, and also nothing to worry about - your lens and/or camera are not broken! Color fringing can, however, be distracting, especially in a printed image, so that is why I am going to show you two quick ways to correct it.
As you can see in this example, there is some magenta color fringing along the subject's arm, and also on a few strands of hair:
There are lots of ways to correct chromatic aberration in Photoshop, so let's look at two of the most straight-forward:
On a duplicated layer, select Filter>Blur>Gaussian Blur:
Adding a Gaussian Blur will help soften the line of the color fringing.
The amount of blur you choose will depend on how large (number of pixels and dpi) your image is. My original image here was around 7000 pixels and 300 dpi, so I chose to blur at a radius of 10 pixels. If your image is smaller, you could choose a smaller blur radius, but 10-15 is a good rule of thumb for the majority of images:
In your Layers palette, set the mode to Color. This will desaturate the color fringe:
Now, select a Hide All Layer Mask so that you do not see the effects of the Gaussian Blur + Color Layer, only the original image:
Click on the Layer Mask to highlight it in your Layers palette. What we will do next is use a soft white brush along the areas where we have color fringing:
What this step does is reveal the hidden layer mask - the layer mask that includes the Gaussian Blur and Color Layer, ONLY on the areas that we brush over. In this example, I used my brush on the subject's arm, and on a few strands of hair. That way, the blur/desaturation only occurs in the areas where I apply my brush, rather than the entire image.
Photoshop CC and CS has a filter that will correct chromatic aberration and color fringing, but it is often hit or miss and sometimes requires more tweaking than the above method. When it works, though, it works very well!
Select Filter>Lens Correction:
Select the "Custom" tab.
In the Custom panel, you will see a section for chromatic aberration which allows you to fix the color casts:
Since this image has color fringing with a green/magenta cast, I took that channel all the way to the left, to -100.
This is an instance where Photoshop's built in chromatic aberration filter worked very well, so you will need to experiment and see which method works best for you, as it may vary from image to image.
Do you have any questions or comments about Chromatic Abberation and how to fix it in Photoshop? Leave us a comment below - we would LOVE to hear from you! And PLEASE SHARE our tutorial using the social sharing buttons (we really appreciate it)!
Anna Gay is a portrait photographer based in Athens, GA and the author of the dPS ebook The Art of Self-Portraiture. She also designs actions and textures for Photoshop. When she is not shooting or writing, she enjoys spending time with her husband, and their two cats, Elphie and Fat Cat.