A Photoshop Color Correcting Tutorial

Photoshop Tutorial Series

Color Correcting | Dodge & Burn | Sharpen

The importance of 50% gray in PhotoShop. Someone complain that their photos look yellowish and reddish, at nights or indoors. The reason is, White Balance. Cameras are stupid, they do not know what pure white is, and they can only guess. Sometimes they are right, but most of time, they make wrong decisions. For example, in a snowy morning, you may get a photo with blue snow. Another typical case is mentioned in the beginning.

So, how to remove the red/yellow cast? How to get the correct color? Follow me!

First, open your photo in Photoshop.

Step 1: Find the half-white/half-black circle icon in the Layers palette and click it. You are going to create a New Adjustment Layer. In the pop-up menu, choose Threshold.

Step 2: You see the pixel gray color distribution in the Threshold dialog. Drag the Threshold Level slider under the histogram to the leftest, and you will find your photo become completely white. Press Up Arrow to increase the Threshold Level, and some of your photo turn into black. That is the the darkest part of your image, or Shadow area. Shift + Left Mouse Button click the darkest area, you will find a eyedropper tool appears in your photo. That is how you locate the Shadow.

Step 3: Repeat the same steps to find the brightest part of your photo, except that dragging the slider all the way to the right this time. And use Down Arrow key to decrease the Threshold Level, until a white area appears. That is the highlight area in your image. Shift + Left Mouse Button click the white area to mark the Highlight.

Since our goal is to find shadow and highlight, and we are done now, then you can click Cancel to delete the Adjustment Layer.

Step 4: Now you have already found the shadow and highlight area, and you are going to locate the most important color, 50% gray. Some tutorials/books leave the most difficult task to readers themselves, only suggesting looking for the area that most likes 50% gray. When I read that part, I feel outrageous! How can a newbie know which grey is?

I did not know it until I watched a great tutorial [2]. And here is its great method. Create a new layer first, and then fill it with 50% gray.

Step 5: Next, in the Layer Blend Mode, choose Difference. Now you get an image with exotic colors, because that is the difference between the original image and the 50% gray. Furthermore, the pure black means the difference is 0, or in other words, it is 50% gray.

So the question is, how to find the black in the image? Same solution as previous ones: use a Threshold adjustment layer. Then we use the eyedropper tool again, to locate the 50% gray. Delete the new gray layer now.

Step 6: Now we know where shadow, highlight and 50% gray are, and Photoshop not. So, let us tell her. Create a new Adjustment Layer, and this time we are going to choose Curves.

Step 7: In the pop-up menu, we see there are 3 eyedroppers, Set Black Point, Set White Point and Set Gray Point. First, let us define black. Left click the Set Black Point, and then press CapsLock key, to make the eyedropper the exactly same size as the one defined by Threshold previously. Move the eyedropper to the location when you defined your shadow area, and when those 2 eyedropper overlap, they both disappear, and that is the time you click left mouse button. Repeat the same steps for White Point and Gray Point.

Finally, press the OK button on the Curve menu. Tada! The color changes! To save it, Flatten Image first.

Compare those 2 images, before and after retouching. You agree that the yellowish and reddish color reduces in the second image, don't you? I hope you like the changes.

Anyway, you can continue to work on the new image, add more saturation and contrast, and then sharpen it. Here is my final version. It may look kind of red/yellow again, but I feel too tired to continue, so my work is done here. ^_^

References

[1] "The Photoshop CS2® Book for Digital Photographers" by Scott Kelby
[2] "Best of PhotoshopUser 7" by Scott Kelby

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