The Clone tool is one of the most incredible tools in the digital editor’s arsenal, allowing you to seamlessly edit your photos with photorealistic quality. When you get really good with it, you can even start to blur the dividing line between photographs and photorealistic paintings.
Before we follow too deep down that rabbit hole, we should start with a crash course on how to use the clone tool in GIMP. The basic method is easy to learn, but tough to master:
Step 1: Select the Clone tool from your tools palette or press shortcut key C
Step 2: Hold down the Ctrl key (the Command key on a Mac) and click to set your clone source
Step 3: Paint just like any other brush tool to recreate pixels from your source point
It’s simple enough to start, but soon you’ll realize that there’s more to it than meets the eye. If you want to learn the importance of selecting a good source point, non-destructive cloning workflows, and how to adjust your clone tool brush to create the perfect invisible edit, read on!
Selecting Your Clone Source
This step is so important that GIMP doesn’t let you use the tool until you’ve selected your source – there’s no way it could work without one. But once you try to correct anything larger than a speck of dust, you’ll quickly realize that your choice of source point can make or break your edit.
The most important thing to remember is to choose a source point that’s as similar as possible to the edges of the area you’re covering. If you don’t blend the edges of your clone stamp properly, they will stand out like a sore thumb to even the most casual viewer.
Pay special attention to light and color gradients in your image. Look for a clone source point along a line running perpendicular to the gradient angle to find sources that will blend smoothly at the edges, although circular color gradients like point light sources can make this a bit difficult.
Advanced Cloning Brush Adjustments
Sometimes choosing the right source point isn’t enough to keep your edits looking smooth and undetectable, and it’s time to adjust your brush settings. They’re mostly the same options as you find in the other brush-based tools, but let’s look at the key ones that you use with the Clone tool.
The most useful keyboard shortcuts for brush tool work are your square brackets [ and ] which control the size of your brush. Sometimes it’s simpler to clone over as small an area as possible, but a larger brush can save time by covering over subtle details that catch your eye.
Adjusting the hardness of your cloning brush is just as important for creating a seamless edit. A softer brush has a more feathered edge with a transparency gradient that helps your brush strokes blend more naturally into the unedited parts of the image.
Being able to adjust brush settings without stopping to focus on the tool settings palette is a huge speed advantage in your workflow, so be sure to get used to using the brackets to tweak brush size and the spacebar to navigate quickly around your image while zoomed in close.
If you really want to stick to the keyboard as much as possible, you can assign new shortcut keys to adjust brush hardness as well as size. Using Shift + [ and Shift + ] keeps things easy to remember, and is a popular configuration among professional retouchers who do lots of cloning.
To set this up in GIMP, open the Edit menu and choose Keyboard Shortcuts. Type ‘hardness’ in the search field, and find the entries Tool’s Hardness: Decrease Relative and Tool’s Hardness: Increase Relative. Click where it says ‘Disabled’ to set a new shortcut key combo.
It’s also a good idea to configure keyboard shortcuts for opacity adjustments. Setting your opacity lower while cloning allows you to gradually build up a ‘patch’ by adding transparent layers together until you have just enough to cover the pixels you want to clone over.
The other two features of the Clone tool you need to know about are the Sample merged option and the Alignment setting. Sample merged is helpful when using layers for non-destructive editing in your cloning work (see more details below), since it samples all your layers at once.
The Alignment settings are a bit harder to explain, but there are three options: Aligned, Fixed, and Registered. Aligned locks your clone source in place relative to your cursor once you make your first click and Fixed keeps the clone source locked in place no matter where your cursor moves.
Registered is more of a special use case that locks the clone source to your cursor, which is only helpful when working with pattern edge matching or cloning directly between layers with no offset. If the Clone tool isn’t working for you, make sure you didn’t accidentally turn this option on!
Whenever you’re editing pixels in an image, your best strategy is to use a non-destructive editing workflow. If you make a mistake or something goes wrong, you’ve always got a backup copy of the source image data to work from. It might be boring, but it can save you a lot of cloning time.
All you have to do is create a new layer and do all your cloning work on that layer. You can do this as many times as you want, allowing you to separate different parts of the image in any way you can dream up. Toggle the layer visibility to quickly see the before and after of your cloning work.
I said the Clone tool was hard to master, and it’s the truth – I’m still refining my techniques after many years of use. But hopefully, after reading this post, you’ve got a much better sense of how to use the Clone tool in GIMP and you’re on your way to creating a perfectly edited masterpiece!About Thomas Boldt