How to Remove Color Cast

Automatic white balance in your modern camera can handle a lot when it comes to correcting the color of an image, but it has limitations and doesn't always remove the color cast completely or accurately. I've found this especially true when dealing with Cokin neutral density filters as they're notorious for creating a distinct color cast when stacked on each other. Now, I could splash out for more expensive filters, but if you know how to remove the color cast in the first place, then you can save quite a few bucks!

The trick has a few steps to it, but it really doesn't take long in Photoshop. Working with a photo I took at the Grand Canyon, I'll illustrate.

Notice that the image has a distinct blue cast in the top half of the image, less so in the bottom half. So, we want to remove the cast without effecting the image quality and detail.

Step 1: Create a group in the layers pallet and call it "Color Cast." Select it.

Step 2: Add a blank layer in the group and name it "Highlights." Select it.

Step 3: Using the foreground color selector or the eyedropper tool, pick an area in the highlights exhibiting the cast.

Step 4: Fill the highlight layer with the foreground color (Option-Delete).

Step 5: Invert the layer (Command-I).

Step 6: Set the mode of the layer to "Color" and adjust the opacity down to somewhere around 8-15%. Play with it a bit, but it's a really light touch there and a matter of taste.

Step 7: Adjust the layer style to apply the correction the highlight areas. Double click on the layer to bring up the blending options and then tweak the "Underlying Layer" sliders in the "Blend If" group. To split the black slider, hold the Option or Alt key and click the triangle. Adjust to something like 25/115 or thereabouts with the two triangles. At this point, you may want to play with the opacity a bit more.

Original Highlights Adjusted

Next, we're going to do the shadow portion of the image. Basically, this is a repeat of steps 2 through 7 with some small variations as follows:

Step 8: Add a blank layer in the group and name it "Shadows." Select it.

Step 9: Set the foreground color to a shadow area with the color cast.

Repeat Steps 4 through 6. For the last step, the adjustment is very similar to step 7, but with the highlights, like so:

Resulting in:

Now, a few more tweaks to remove the haze and sharpen it up...

Original Final Result

There you have it, color cast adjusted, though there are some addition tweaking that could be done, the sky is a bit "meh" from a detail and look perspective. I'd likely crop that out if I was to print this.

I find that you can also do this a couple of times on the same image, picking different highlight and shadow areas. That's what I did with the dancer from the Tropicana Club in Havana, a challenging scene given that the lighting colors were very mixed.

Many thanks to Michael Woloszynowicz of Vibrant Shot for his great YouTube videos including the how-to for this technique. While you're there, check out his fantastic sharpening techniques where he also supplies you the photoshop actions. Worth subscribing to his channel.


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