In Krita, selection tools can be used to select areas of the canvas in order to restrict the effect of operations. Selections are also useful to fill whole areas of the canvas with a single color or pattern, and to create masks for filters and other effects.
Shape Selection Tools
There are a few tools that behave just like Krita's drawing tools, except they create selections instead of drawing shapes. They are:
- The rectangular selection tool.
- The elliptical selection tool.
- The polygonal seelction tools.
- The Bézier curve selection tool.
It's worth noting that if you're working with selections a lot, GIMP is probably a better software for your task. In Krita, when you use the rectangular tool, for example, you click and drag to draw a rectangle, and when you release the mouse button, it becomes a rectangular selection. In GIMP, tools generally do not apply their effect when you release the mouse button, merely displaying a preview and allowing you to edit their effect before continuing. This can feel extremely clunky in some workflows, but in others, it's very useful to change be able to precisely change where a rectangular selection starts and ends, for example, without having to undo it every time you make a mistake.
Lasso Selection
Krita has a lasso selection, but it's labelled "Freehand Selection Tool," and it doesn't come with any keyboard shortcut by default, which feels rather strange as this is probably the selection tool that is most useful for artists.
With the lasso tool, you draw a "lasso," i.e. a circle around what you want to select, and it becomes a selection. The lasso tool automatically connects the start to the end of the lasso, so generally do not draw a closed circle, you leave a gap that's automatically completed.
Magic Wand
Krita has a magic wand tool, that has the icon of a magic wand, but is labelled "Contiguous Selection Tool." This tool is used for selecting areas of similar color. For example, if someone is wearing a red shirt, and you want to select the whole shirt, you would click on the shirt with this magic wand, and an algorithm would be executed to select an area based on the pixel you clicked on.
This is a tool you use if you're working with photos.
Like any magic wand, it has a setting in its tool options to change the "threshold" of the magic wand. Essentially, if you click on a pixel, and the "threshold" is at its minimum value, then only pixels the exact same color as the pixel you clicked on will be selected. The higher the "threshold" the more different the pixels can be compared to the starting color. At maximum "threshold," the magic wand becomes useless because it's always going to select all pixels in the canvas, since it's going to allow even completely different colors.
In general, the magic wand is always going to select either too much or too little, so you will need to combine multiple selections together to make it select what you want to select, and nothing more. In Krita, hold Shift before clicking with the magic wand to add the new selection to the current selection, and hold Alt to subtract it instead. So if it's missing a spot, you hold Shift and click on it, and if it selected too much, you hold Ctrl and click on a color it's not supposed to select.
Note: in GIMP, it's possible to control the threshold of the magic wand by clicking and dragging. The farther you drag, the higher the threshold gets. Krita lacks this functionality.
Using the Magic Wand for Line Art
In Krita, the magic wand can used to select colors based on the current layer's color, the colors of all combined layers, or colors of specific layers. The latter is useful if you're working on a coloring layer and you want to select areas based on line art layers.
To do it, first you need to right click on a layer to open its context menu, and then change the color label of the layer under "Layer Style...." For example, you make the line art layers blue-colored, or the group that has all line art layers blue-colored. Then, in tool options, you select the blue color for the magic wand. Now the magic wand will only consider the line art layer when selecting areas.
Note: in Clip Studio Paint, the system is simpler: you can only have one layer or group marked as the "selection source," so you can quickly switch which one is the source without having to right click or think about color labels.
The same functionality exists for the paint bucket tool.
In the tool options for Krita's magic wand you'll also find the ability to automatically grow and feather the selection by an amount. If you select a white background with black ink on it, for example, and you try to delete it or change the area's color, you'll probably get some jagged white outlines around what wasn't selected. You can use grow and feather to try to increase the selection to cover those outlines as well.
Note: these functions can be applied on any selection through the "Select" menu on the menubar, which is kind of weird if you think about it: why does magic wand have this, but circle does not? Why not just have this option for every one of them?
Brush Selection Tool
Some applications like Photoshop and Affinity Photo have a tool that is similar to a brush that you use to select areas of the image, but acts closer to a magic wand. Unfortunately, neither GIMP nor Krita have such tool.
Similar Color Selection Tool
This tool selects all pixels that have a similar color to the one that was clicked on, but it does so in the entire canvas, regardless of where you clicked on. To elaborate: the magic wand "grows" the selection from the starting point, and stops when it can't find similar pixels anymore, while this tool just looks at each pixel individually and compare its color to the color you clicked on to decide if it's selected or not.
For example, imagine you had a checkerboard pattern, squares of alternating colors. If you used the magic wand to select on color, you would have to click on each square individually, because the selection would stop the second it met the pixels of the other color. With this tool, it would select the entire board with a single click, so it's suited for removing a color from a pattern, for example.
Magnetic Curve Selection Tool
This tool is similar to the lasso tool, except that it has an algorithm to make the lasso automatically attach to pixels that have high contrast, so it can be useful for selecting shapes with more precision than the magic wand allows.
Leave a Reply