Digital Diversity

Chromatic Aberration and Purple Fringing are a common problem in cameras with anything but high class lenses. It is very common on fixed lens cameras of all kinds as well. Some will get rid of it on the JPEGs for you with in camera software but if you shoot RAW then this doesn’t help you. CA and PF are both fairly ugly and take something away from an image as it gives adds unnatural coloured outlines. However you don’t need to worry because they can be fairly easily removed using Photoshop.

So what is Chromatic Aberration and Purple Fringing?

These 2 phenomenons are basically the same. Chromatic Aberrations are the colour lines you get on the edge of high contrasting parts of an image. Purple fringing is the same except its purple.

How can you remove it? Well, with Photoshop of course.

Removing chromatic aberration in Photoshop CS

If you have the full version of Photoshop you can take care of small chromatic aberration problems with a handy built in tool.

Go Filter > Distort > Lens Correction. This will open op a new window with several tools at your disposal. Elements does have a version of this but it doesn’t contain the CA correction sliders.

Just move these sliders till the CA disappears. On images that suffer a lot of CA and PF this may not work so well. If thats the case you will need to take the longer route.

Fixing CA and PF in both CS and Elements

For this tutorial you will need to know how masks and adjustment layers work.

The image below has suffered quite badly from both CA and PF.

Zoom into the bottom right too clearly see these 2 effects.

To remove these you can use a few Hue / Saturation adjustment layers. Add one to your layers window above the main image.

From the drop down menu select Cyans. Now adjust the Hue, Saturation and Lightness sliders till the cyan CA blends in to the rest of the image. Dont worry too much about the colour changes to the rest of the photo for the moment.

Now change the drop down menu to Blues and repeat the process.

Re-name the adjustment layer Cyans and Blues.

Create another Hue / Saturation adjustment layer. Re-name it Reds. Find an area of your image effected by red / purple fringing. Repeat what you did with the last adjustment layer but this time on the Reds and then Magenta channels.

Before

After

When you are happy with the result create a third Hue / Saturation adjustment layer and call it Greens. Find an area that has bright green lines and do as before but on the Green channel.

Before

After

With all the CA and PF taken care of you now need to use the masks so that it only affects the parts of the image where needed. Invert all your adjustment layers mask so they are black. To do this, hold down alt then click the mask. The screen will go white. Press Ctrl I and they will go black. Repeat this for all 3 adjustment layers masks

Starting with the blue and cyan correction layer use the masks to reveal the corrections you made over the CA and PF on the image. Then repeat this for the other 2 adjustment layers. The final result should look a lot nicer. You can even go back to each adjustment layer and tweak them further if needed.

Tags: adjustment layers, advanced masks, chromatic aberration, colour correction, colours, contrast, elements, highlights, hue, layers, lighting, masking, masks, panasonic fz28, panasonic lumix fz28, photo editing, photography, photoshop, purple fringing, saturation, thoughts, tutorial, tutorials

This entry was posted on Friday, September 11th, 2009 at 14:45 and is filed under photography, photoshop. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.