Hi everyone :)
I'm back again with another quick tutorial for you to help you with processing your images. In previous posts, I've talked about the Levels tool as a way to add contrast and correct exposure, and also about the Color Balance menu as a way to get the right overall color to your picture.
Sometimes, however, there is a little bit more to the whole color side of things.
To start with, here is our image - we have now adjust the contrast and exposure using Levels, and have adjusted the color using Color Balance.
Now it's time to look for anything else that's happening that might look a little strange. This part is definitely a little bit more 'personal' to you, in the sense that what I spot and what you spot might be different. Essentially, light bounces (you knew that though!). When it does, it often reflects or bounces off colored surfaces. That fact, combined with the way that your digital camera attempts to interpret and render color, means sometimes an image comes out with some colors that we don't really want in the picture. Sometimes, those colors were 'really' there - for example, if you placed someone right beside a bright green wall, their skin tone might look a little more green than usual. However, we often like to correct these color casts so that the image looks more the way we might have expected it to.
In this image, I can see straight away that her dress doesn't really look black - it looks like there is a tint of something else in there too. If you spot something like this in an image, and want to remove it, here's a good place to start. The Hue/Saturation menu (use an adjustment layer) allows you to adjust the saturation for separate colors in the image individually (Red, Cyan, Green, Magenta, Blue, Yellow), so you can tone down or completely remove that color that is causing the color cast, and then apply it only to the area it's not supposed to be in. First though, you need to know what that color is! Create the Hue Saturation Adjustment Layer (Image > Adjustments > Hue/Saturation) and notice that when the dialog box pops up, it has a little drop-down box set to Master. That means that the sliders currently adjust all colors in the image at once, which is not what we want to do. Take a guess at what color the cast might be. It doesn't matter if you're wrong, but pick one - I'll pick Yellow just to show you - it doesn't matter at all! I select Yellow from the drop-down box. If you move your mouse at this point, you'll notice that the cursor has changed into an eyedropper. Click on the area that you think has a color cast. When I click on the girls dress, the drop-down box immediately changes according to what color the eyedropper found - in this case Cyan. Then, in order to 'see' the cast, I bump the Saturation slider right up to 100% to see what is affected.
Based on the different saturations, I can see that there is a lot of cyan in the background, a little on her dress and also some in her hair. So I remove all of the cyan, by sliding the Saturation slider to 0.
When I do that though, I notice that the background just doesn't look right without that color in it. This is why we use Adjustment Layers - they come with a built in layer mask that lets us say where the effect should apply. With the Hue/Saturation adjustment layer selected, I press Ctrl-I (on the PC) to invert the layer mask. That means that my image looks just like the original, as I haven't suggested anywhere that my color cast removal should apply yet. I click on the Layer Mask of the Hue/Saturation adjustment layer in the Layers Palette, and then I go and select the brush tool from the Toolbox. I paint with a soft white brush (if I had wanted to remove areas of the effect and I hadn't inverted the mask, this would have been a black brush) over her dress and hair. This gives me this result - with color cast removed:
That's it! It's very easy to do and can really help, especially when color casts are strong. Don't forget though - there can be more than one color cast on any one area of your photo :)
Next week, I'll briefly discuss some of the finishing touches - tools for blemishes etc, sharpening, the eyes, vignetting & cropping.