2.3 Adjusting your photo
Now that you have a basic graph built, let’s insert a new node to change how your photo looks. Similar to when you added the Image Open node, left click the “Color” button in the top left with the sliders icon . Then left click “HSL Channels” in the pop-up menu. You will see a HSL Channels node appear. If the nodes are overlapping each other, move them by left clicking on their title bars and dragging.
HSL stands for hue, saturation and lightness. The HSL Channels node adjusts the hue, saturation and lightness of an entire image.
To use the HSL Channels node, we must insert it between the Image Open node and the Render node so it can process your imported image. There are a couple of ways to insert a node between two nodes that have already been connected to each other. The first way is to move an existing connection from a node to the node being inserted and then adding a new connection from the inserted node back to the node that was originally connected. This might sound complicated but it’s straight forward with a little practice.
Let’s insert the HSL Channels node between the Image Open node and the Render node using this first method. Press and hold your left mouse button on the white anchor on the left side of the Render node, then move your cursor to the dark “Image” anchor on the left side of the HSL Channels node and release your left mouse button. The connection will move. To finish inserting the HSL Channels node, you must connect it to the Render node. Just like earlier, press and hold your left mouse button on the dark “Image” anchor on the right side of the HSL Channels node, move your mouse over the dark “Image” anchor on the left side of the Render node, and release your left mouse button. When done correctly, the Image Open node will be connected to the HSL Channels node which will subsequently be connected to the Render node.
The second way to insert a node is to click and drag the node over an existing connection. The connection will turn yellow to indicate that releasing the node will insert it. This method is much faster but it isn’t always available so it’s important to be familiar with both methods. See Inserting Nodes Into Connections for more details.
With the graph all setup, you are free to left click and drag the Hue, Saturation, and Lightness sliders in the HSL Channels node. You will notice the thumbnails for the HSL Channels and Render nodes will change but the Image Open node will stay the same. This is because the thumbnails in each node shows a preview of their respective output. As you build more complex graphs, you’ll find these thumbnails useful for quickly figuring out which nodes are doing what.