The Paint Tool is a general purpose drawing tool for modifying a reflectance or illumination field. The Size, Hardness, and Flow parameters control the shape and effect of the brush. The Size specifies the diameter of the brush. The Hardness specifies the brush profile, with a lower Hardness producing a more feathered profile. The Flow specifies how much the brush modifies the image.
The Tool Options panel shows the current color of the Paint Tool. There are three ways to specify the color. (1) The user can edit the R, G, and B text fields in the Tool Options Panel. (2) The user can click on the Eyedropper button, then click in the main window to select a color from the currently visible image. As a shortcut, holding down the option key while the Paint Tool is active converts the tool into an eyedropper until the option key is released. (3) The user can click on the Color Picker button and use the standard color selection tools to choose the color.
It is important to note that the range of the color values in the reflectance and illumination fields is not limited to between zero and one. It is not uncommon, especially in the illumination field, for the RGB values to exceed one. High dynamic range images, in fact, may have values of up to 100. While values outside of the range [0, 1] are not a problem within Lightbrush, they may cause problems when exporting to non-EXR formats, such as TIFF images.