06-20-2021, 04:54 PM
As always with Gimp there are several ways, this is just one.
The palette is the easy part. If the palette dock is missing go to Gimp menu Windows -> Dockable Dialogues -> Palettes and that will get you the available palettes. Choose one and click on it. That brings up the palette editor where clicking on a colour sets that colour as the Foreground colour, the one the paint tool uses.
Specifically for black lines on a white background.
Make a new layer on top Layer -> New Layer (default is transparent)
Set the layer mode to Lighten only
Use the paint tool, set a brush and size (not particularly important in this case)
Choose a colour and paint over the line.
Make a mistake, use the eraser tool.
This a 60 second animation of that. https://i.imgur.com/irNJQ3l.mp4
If you want to use a specific size brush to paint over a line and keep the general 'track' of the line then it becomes more involved. Usually you will create a path then stroke the path with a color and size.
Quote:...I want to have a fixed palette of half a dozen or so different colours that I can select one of, then be able to brush over part of my image so that anything which is black gets changed to the colour I've selected.
The palette is the easy part. If the palette dock is missing go to Gimp menu Windows -> Dockable Dialogues -> Palettes and that will get you the available palettes. Choose one and click on it. That brings up the palette editor where clicking on a colour sets that colour as the Foreground colour, the one the paint tool uses.
Specifically for black lines on a white background.
Make a new layer on top Layer -> New Layer (default is transparent)
Set the layer mode to Lighten only
Use the paint tool, set a brush and size (not particularly important in this case)
Choose a colour and paint over the line.
Make a mistake, use the eraser tool.
This a 60 second animation of that. https://i.imgur.com/irNJQ3l.mp4
If you want to use a specific size brush to paint over a line and keep the general 'track' of the line then it becomes more involved. Usually you will create a path then stroke the path with a color and size.