How To Use Quick Mask Mode In GIMP {Complete Guide}
GIMP provides a lot of tools for making selections to edit and retouch your images. One of the most overlooked tools for making selections is the Quick Mask Mode. It’s my go-to tool for selecting. And I also use it in conjunction with other tools for fine-tuning selections, like the Intelligent Scissors tool, Fuzzy Select, Foreground Select, Gradient Tool, and others.
In today’s article, you’ll discover the magical powers of QuickMask, what it is, and how to use it. If you’re ready… let’s do it!
What Is the QuickMask Mode In GIMP
Photo by Daria Shevtsova. The red overlay has been placed on the whole image except for the suitcase. Which I targeted as the selected part of the image.
The QuickMask mode was designed to select or “mask” out an area quickly and easily. Its function is similar to that of a Layer Mask, except it’s used to define a selection.
QuickMask mode can not be found in your toolbar! That’s probably why you’ve never known that it existed. The tool is tucked beneath your vertical ruler and is denoted by a square icon.
Clicking on that icon will activate the mode and will apply a red overlay on your image. This is used as a visual showing what is and isn’t part of the selection. You can also use a keyboard shortcut to turn on the mode with Shift + Q.
GIMP Quick Mask Settings
Settings for the QuickMask are not in the Tool Options and are hidden too! To access the options right-click on the icon to reveal a pop-up menu with 4 items.
- Toggle QuickMask: This will turn QuickMask mode on or off. Although, I find it's quicker to use Shift + Q.
- Mask Selected Areas: This setting will remove the red overlay until you begin painting with black. Any area not in red will be part of the selection.
- Mask Unselected Areas: This setting is set by default, and anything in red will not be part of the selection.
- Configure Color and Opacity: Use this setting to change the overlay color and change its Opacity setting.
How To Use Quick Mask Mode with GIMP
Like with a Layer Mask, you’ll paint with white to add and black to remove. Most of the time, you’ll use a Paintbrush to define your selection as needed. Using a soft-edged brush will allow you to feather the edges to keep the selected area from becoming jagged.
When applying a Paintbrush, you’ll want to use a keyboard shortcut as you work, which is the letter “X.” This alternates the Foreground and Background colors. You’ll also want to speed up your workflow by setting up your mouse wheel button to increase or decrease the brush’s size as you work.
Keep in mind, any selection tool can be used to remove or add from the selection too. This is achieved by setting the background color to black and deleting it to remove it from the selection. Or to add to it, set the background color to white and then delete.
QuickMask + Channels
When using the QuickMask mode, a new channel is created for its content. This can be seen in the Channels panel. To make it visible, go to Windows > Dockable Dialogs > Channels.
Inside, you’ll find a Red, Green, and Blue channel. Just below those, you’ll see a Quick Mask channel too. You might also see an Alpha Channel if you’ve added transparency to the image. This new channel will only be available when in QuickMask mode and disappears when deactivated.
While in the mode, you can convert the defined selection into a Layer Mask and have all the benefits of them. This also gives you the ability to transfer a selection to another image.
Creating a Layer Mask from QuickMask mode can be done as you’ve done before. Make sure you’re still in the mode before doing so. Inside the “Add Layer Mask” window, choose “Channel” and click Add.
Save the Selection
Once you deactivate the QuickMask mode, the channel disappears. However, you can create a permanent channel, which in essence saves your selection. To create a channel…
- Go to your menu, under Select > Save to Channel. This will only work if the "marching ants" are still present.
Transfer the QuickMask Selection To Another Image
Now that you’ve created a permanent channel, it can be used on a different layer and or image.
- To add to another layer: Make sure the correct layer is activated and add a Layer Mask > Channel as before.
- To add to another image: Make sure the channel is selected and add the marching ants as you did previously. Switch to QuickMask mode and copy the content with Command or Ctrl + C. Go to the tab with the new image, turn on QuickMask, and paste with Command or Ctrl + V. Then, click the Anchor icon at the bottom of the Layers Panel and turn off the mode.
What's Next?
Hope you enjoyed today’s tutorial! If you’re ready to elevate your GIMP editing skills, I have another tutorial or two or 100 for you here. Plus, you may want to check out this tutorial too.
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