5.3 Putting it together
Using a combination of blending and masks, you can restrict changes to specific parts of your image. In this section, you’ll use these concepts to change the hue of a subject while leaving the rest of the image unchanged.
Next, insert a HSL Channels node between the Image Open and Render nodes and change the hue. This will affect the entire image but you will localize the adjustment in a moment.
Now add a Blend node. Connect the output of the HSL Channels node to the New Source input anchor on the Blend node, the output of the Image Open node to the Destination input on the blend node, and the output of the Blend node to the Render node. The canvas won’t look any different because you still haven’t added a mask yet.
Add a Paint Canvas node and connect its input to the Image Open node or HSL Channels Node. It doesn’t matter which because the Paint Canvas Node only uses the input image’s size and both of the nodes in this graph produce images of the same size. Then connect the Paint Canvas node’s output to the Mask input anchor on the Blend node.
Finally, select the Paint Canvas node, click the Brush tool on the Tools Toolbar, and paint over the background. You’ll notice that the original image will show through where you paint. This is because, by default, you will be painting black on a white background which allows the image below to show through. If you make a mistake, you can undo by pressing Ctrl+Z or change the brush color to white and paint over it.
Make sure to practice and experiment with this technique. You’ll find it invaluable when perfecting your photos.