Paint Tool

The paint tool lets you paint a solid color freehand over an image using a brush with adjustable radius, transparency, softness, and color.

Once the brush parameters (described below) are set, you paint strokes on the output image by clicking and dragging. You can also set the brush color from the underlying image by shift-clicking on the image. Unlike most other transformations, the paint tool works directly on the output image and not on the input image.

The paint tool records the dimensions of its input image internally. If you try to apply the paint tool to another image whose width and height in pixels does not match the original input image, an error is reported.

Amount

The amount control lets you scale back the overall paint transparency or you can create a mask to restrict painting to specific parts of the image.

Brush Settings

The following settings determine the brush properties:

Radius

This slider controls the radius of the brush in pixels. Smaller brushes are good for creating fine detail. Larger brushes are good for filling big areas quickly. In addition to using the radius slider, you can also use the mouse scroll wheel to adjust the radius.

Transparency

This slider controls the transparency of the brush. The more transparent the brush, the more the background shows through.

Softness

This slider lets you control how soft the edges of the brush are. The softer the brush, the more smoothly its effects are blended with the original image.

Spacing

This slider lets you control the spacing interval at which the brush is applied as you drag. The smaller the spacing, the more the applications overlap. Too much overlap can lead to a heavier application of the brush than you intended, so you may need to increase the transparency. Too little overlap can leave gaps.

Fadeout

This slider lets you make the brush effect fade out as you draw each stroke, effectively increasing its transparency the further you drag from the starting point.

Shape

 The brush shape tool bar has three options: round, square or diamond. Usually a round brush is fine, but occasionally a different brush shape helps you get into corners hard to reach with a round brush.

Mode

Copy/Lighten Only/Darken Only

These settings control how the painting operation is performed. Lighten Only just paints where the brush color is lighter than the current image. Darken Only just paints where the brush is darker. Copy paints in both situations.

HSV Hue Only/HSV Hue and Saturation Only/HSL Hue Only/HSL Hue and Saturation Only

These settings let you restrict painting to the hue or hue and saturation channels of the image. This lets you change the color of a region without altering its brightness. This is especially useful for colorizing black and white images.

Brush

If you select Single, then a single brush application is performed when you click on an image and is not repeated as you move the cursor with the mouse button depressed. The default setting is Continuous which keeps painting so long as you hold the mouse button down.

Stylus Pressure

If you are using a pressure-sensitive stylus, this control lets you determine the effect, if any, that stylus pressure has on the current brush stroke. If you are not using a tablet, this control is set to Ignore and the other options are grayed out.

Ignore -- stylus pressure has no effect.

Controls Opacity -- increasing stylus pressure reduces transparency, making the stroke more opaque.

Controls Radius -- increasing stylus pressure increases the brush radius, making it larger.

Controls Hardness -- increasing styles pressure reduces softness, making the edges of the brush harder.

Controls Flow -- increasing stylus pressure reduces spacing, causing the brush to be applied more often as you move the stylus.

Color

This control lets you select the paint color. To choose a paint color right off the screen from an image, shift-click on the spot whose color you want to select.

 Undo/Redo

The undo tool bar lets you undo paint operations, one stroke at a time. A stroke is defined as everything between pressing the mouse button and releasing it.

If the undo or redo button is grayed, it means there are no operations left to undo or redo. If you undo too many operations by accident, you can click the redo button until you get back to where you wanted to be. However, once you draw a new stroke, you can no longer redo past that point.

You can use the keyboard shortcuts Ctrl-Z for undo and Ctrl-Y for redo.

Brush Display

As a visual aid, a representation of the current brush is displayed at the bottom of the dialog box. This display illustrates the radius, transparency, shape and softness of the brush. If you select a very large brush radius, part of the brush may not be visible.

 Settings Menu

Saving a Paint settings file saves all the accumulated paint operations and not the current brush settings. Reloading a previously saved Paint settings file re-applies all the saved paint operations to the current input image. Since paint operations are specific to both the size and the contents of the input image, Paint settings files have limited utility. Creating a default Paint settings file is likely to cause warnings about file size mismatch every time you use the Paint tool, so this is not recommended.

In addition to the standard menu items, the settings menu lets you load or save the current brush settings (Radius, Transparency, Softness, Spacing, Fadeout, Shape, Mode, Brush, and Color). Brush settings can be shared with the Clone and Smudge tools. Settings unique to these other tools are set to default values when saved from the Paint transformation. You can also use the Settings menu to select the probe radius when you click on the input image to select the paint color. You can also save the current brush settings as a default brush which is loaded whenever the Paint transformation starts up.

When saving Paint settings as default settings, no strokes are saved since it generally does not make sense to apply painting from one image to another, especially if it has different dimensions.

Tips

You cannot paint in color over a black and white image without first converting it to a color image. You can accomplish this conversion by running the image through the Convert transformation.

Keep your strokes short – that way if you accidentally paint over a spot you did not intend to cover you can undo it without having to redraw too much.

Try to use as few strokes as possible – overworking an area can muddy the image.

The Lighten Only Mode setting can make painting easier in some cases such as removing dark objects against a light background. When you paint over dark areas with a light color, only the dark bits are replaced. Similarly Darken Only is useful for removing light objects on a dark background. To further refine what areas are affected by the paint tool, you can create an amount mask based on properties of the underlying image such as color, brightness or texture.