Photoshop CS5 Merge to HDR Pro – Ghost Removal and Colors

Burning waters @ Orlando WetlandsBurning waters @ Orlando Wetlands – Sunrise and flowers at Lake Searcy

I’ve been using Photoshop CS5 for a while and I really like the new capabilities.  Using  content aware fill to delete/ replace areas in photographs works amazingly well.

The new “Merge to HDR Pro” also works better than the CS4 version.  I had also been very impressed with the “Remove ghosts” check box when merging images into an HDR.  This automatically identifies and fixes features in the image that move between the multiple exposures used to create the HDR.  In the image below, the wind was blowing and caused the flower to move between shots.  It shows how effective the automatic Ghost removal can be.

Left: Ghost removal off;  Right: Ghost removal on
Left: Ghost removal off; Right: Ghost removal on

But…  I’ve noticed some issues with color when using CS5 to create several of my HDR photos.  Very bright areas sometimes have sections that are discolored, as in the example below.

Discolored areas in CS5 HDR image processed with Ghost removal on
Discolored areas in CS5 HDR image processed with Ghost removal on

This puzzled me until I discovered today that the discolored area seems to be related to Ghost removal.  Here is the same image, but this time processed with Ghost removal off.  You can see that the discoloring is gone (or at least greatly reduced).

Discolored areas in CS5 HDR image do not appear with Ghost removal off
Discolored areas in CS5 HDR image do not appear with Ghost removal off

So, how can you get around this problem if you have bright areas like a sunrise or sunset and you want to use Ghost removal?

What I did was run the Merge to HDR twice – once with Ghost removal on and the second time with it off.  Then I copied the results into separate layers in a single file and used a layer mask to select which version I wanted in different areas of the photo. For the sky, I chose the layer with Ghost removal off and for the foreground area with moving vegetation, I used the layer with Ghost removal on. It is an extra step, but definitely worth it for an image you really like, like the one at the beginning of this post.

©2010, Ed Rosack. All rights reserved.

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