Join Tim Grey for an in-depth discussion in this video Removing strong color casts, part of Photoshop: Image Cleanup (2013).
For certain image clean up techniques I find that I really only use them in certain situations. While some of the tools available for image clean up can be applied to a wide variety of different possibilities, for the technique I'm going to show you here, there's really a fairly narrow set of situations where you might utilize the technique. Specifically you're most likely to use this option when you have an older image that is faded in such a way that there's been a very strong color shift. This image for example is a scan from a print, and that print had been stored in an album for a number of years, and it became faded over time shifting into a sort of reddish magenta tint. And we're going to resolve that color issue very quickly and easily. Let me show you how it's done.
I'm going to start off by creating a copy of my background image layer. So I'll drag the thumbnail for my background layer down to the create new layer button. The blank sheet of paper icon at the bottom of the layers panel. And now, I want to determine the color of this very strong color cast. And to do that, I'm essentially going to determine the average color of the entire image, in other words the average of all pixel values. To accomplish that, I'll go to the filter menu and then choose blur followed by average, and what this does is essentially is blur the image so much that the result is a single color, the average color for the entire image. I'll go ahead and choose that option, and you can see sure enough that average color is a variation on magenta you might say, somewhere in the red to magenta range.
But of course this is the problem color. And I want to essentially remove this color, so I want the opposite. I'm going to move my image into the opposite direction. And so I'll invert this particular layer to get the opposite color. To do that, I'll choose image and then adjustments, followed by invert. I could also press Control I on Windows or Command I on Macintosh to execute that command. And that gives me a shade of sort of greenish, which would be the opposite of a somewhat magenta color, and that color represents the direction that I want to move this image into. Well I can apply that color directly to the underlying image simply by changing the blend mode for this layer.
So I'll go to the top of the layers panel and click the blend mode pop up, and down toward the bottom I'll choose color. And this causes the layer that I've created here, to only effect the color of what's beneath. And so the tonality, the texture is showing through as it were. It's as though I took a green sheet of acitate and laid it down on top of the print. But of course the effect is a little bit too strong. Well, a lot too strong, and so we need to tone down the result. To do that, I'll go to the Layers panel once again, and use the Opacity control to reduce the opacity for this background copy layer.
The specific value, you'll use will vary a bit, depending on the particular circumstances, but generally you'll find that it will be somewhere in the range of 50%. If the value is too low then you'll still see some of the original color showing through, that strong color cast, and if it's too high the image will take on the color cast off the background copy layer that we created. So usually right around 50% will give us a good balance, but you'll want to fine tune. To get the most accurate color possible in the image. Once you've achieved that result, obviously we've done a great job of removing the color cast, but the image is a little bit flat, there's not very much saturation.
So there will certainly be other adjustments I need to apply. I want to enhance contrast an boost saturation at the very least, in this particular case. And I might apply some other fine tuning adjustments, but we're off to a great start with this image. I'll turn off the visibility of the background layers so we can see the original. And then turn it back on again, and you can see the result with a very simple process, just creating a background copy, applying the average blur to that copy, and so we've achieved a great result with a very simple technique. All I need to do is create a copy of the background image layer, apply the average blur filter, and then invert the result, change the blend mode to color, and reduce the opacity. Of course its always a good idea to keep your layers panel organized. And so I might want to rename my background copy layer to something more meaningful.
I'll go ahead and double click on the name and type a new name for that layer. And then press Enter or Return on the keyboard to apply the change. But there you have it. A very quick and easy way to take care of a very strong color cast in a photo.
- Cleanup concepts
- Essential cleanup tools
- Basic cleanup techniques
- Removing strong color casts
- Adjusting brush shape
- Extending the frame
- Using multiple exposures
- Replacing a bad sky