Luminosity Masks have become a go-to technique for many photographers wanting to make selective adjustments on their images. While it’s a great way to create precise masks, it’s a mask solely based on the luminosity of a pixel and it may not be ideal when you only want to make adjustments to a specific color. Perhaps you want to enhance that beautiful sunset you photographed last night or maybe you want to change the color of your subject’s eyes. Regardless of what color based adjustment you want to make, there’s a simple and quick method of creating a precise selection based on the color value using Photoshop’s Color Range Tool.
Why Use Selective Adjustments
Before we jump into how you can create a precise selection based on a color, I quickly want to talk about why you should be using selective adjustments in your post-processing.
My area of expertise is landscape photography but this topic is important no matter what type of images you capture or your ambitions. If you have a desire to make your images look better, you need to be making some selective (local) adjustments to them.
It doesn’t need to be anything super-advanced, but start by at least making some selective color adjustments. The main reason you’d want to do this is to get rid of the unwanted color cast. The color cast can come as a result of your previous post-processing or it can come straight from the camera and it’s something that sticks out as a negative when viewing the image (the exception is when it’s a deliberate color cast that serves a purpose).
It’s also quite common that you’ll want to make an adjustment only to a specific area of an image (known as a local adjustment). A normal adjustment will affect the entire image (known as a global adjustment). Instead, create a mask that selects only the part of the image you want to affect (for example the highlights, a color, or maybe just a specific subject) and make your adjustment. Now, you’ve kept the majority of the image untouched but have made a visible adjustment to that particular area – no global color cast and no unwanted effects.
Create a Mask Based on Color
Okay, let’s jump into it and start making a few adjustments based on a color. In the example below, I want to increase the saturation and brightness of the yellow flowers in the foreground. A typical way of making a similar adjustment would be to use the Hue/Saturation adjustment and increase the saturation of the yellows. Yes, the flowers are saturated and brighter now but so are the cliffs, areas in the sky, and even some of the water.
First of all, make sure that you’re on a Stamp layer – in other words, one which is all the layers below it merged into one (you can delete this layer later but you’ll need it for the next step). Now, go to Select > Color Range… A new box should now appear and it’s here that you’re going to create the mask.
For the best results, make sure that Sampled Colors is selected in the top drop-down menu. It’s possible to work with the other options as well but I find the mask to be much more accurate by manually sampling the colors you want. Next, with the Eyedropper Tool selected, click on the color in your image that you want to select. For me, that’s one of the yellow flowers in the foreground. Notice that the image within the Color Range box now has changed and it’s mostly black. This represents the selection we’re making (only the white parts of the mask will be affected).
Refine the mask
The Fuzziness slider is a useful tool to make the selection more or less refined. By pulling the slider towards the left, you’re creating a more restricted mask and it affects less of the similar colors to what you’ve selected. Pulling it towards the right has the opposite effect and the mask starts including similar colors. I prefer to use a fuzziness of approximately 70-80 but I recommend you play around with it for each shot.
That’s it! Click OK and you’ve created a precise mask based on that color. Now, you choose the adjustment you want to use – I’ll use the Hue/Saturation slider for now.
Adding Colors to the Selection
Before we continue and start enhancing the image, I want to show you how you can add more colors to the mask. Let’s say that I also wanted to make the same adjustment to the bright parts of the sky. Before clicking OK and creating the selection, I would simply hold shift (or select the second Eyedropper Tool named “Add to Sample) and click on the sun. You’ll see that the mask has changed and the area around the setting sun is also whited out.
Unfortunately, this step also included some of the cliffs in the lower right corner which I don’t want to be affected. The best way to remove that from your mask is to paint directly on the mask with a black brush after creating an adjustment layer.
Making the Adjustment
The last thing I’m going to do is to increase the saturation and brightness of the flowers. With the mask we created active (you know it’s an active mask when you see the marching ants around your selection), create a new Hue/Saturation Adjustment Layer. Since we’ve already created a mask that targets only the yellow flowers, we don’t need to go into the yellow channel, instead, we continue using the Master channel.
Now just drag the Saturation slider towards the left until the colors are saturated to your taste. I also increased the Lightness slightly to make the flowers pop even more.
This technique of creating a precise mask can be used with any adjustment layer that you want. I often combine it with any color-based adjustments such as Hue/Saturation, the Photo Filter, and Color Balance. For adjustments that affect the brightness and contrast of the image, I prefer using Luminosity Masks.