This tool fills a selection with the current foreground color. If
you Shift+click and use the Bucket tool, it will use the
background color instead. Depending on how the tool options are
set, the Bucket Fill tool will either fill the entire selection,
or only parts whose colors are similar to the point you click on.
The tool options also affect the way transparency is handled.
The amount of fill depends on what Fill Threshold you have
specified. The fill threshold determines how far the fill will
spread (similar to the way in which the magic wand works). The
fill starts at the point where you click and spreads outward until
the color or alpha value becomes “too different”.
When you fill objects in a transparent layer (such as letters in a
text layer) with a different color than before, you may find that
a border of the old color still surrounds the objects. This is due
to a low fill-threshold in the Bucket Fill options dialog. With a
low threshold, the bucket tool won't fill semi-transparent pixels,
and they will stand out against the fill because they have kept
their original color. If you want to fill areas that are totally
transparent, you have to choose right-click|Select|Select All, and
make sure that the layer's “Keep Transparency” button (in
the Layers dialog) is unchecked. If the Keep Transparency button is
checked, only the opaque parts of the layer will be filled, and if
you don't use the Select All command, only the opaque
“island” that you clicked on will be filled.
The Bucket Fill can be called in the following
order, from the image-menu:
The Tool can also be called by clicking the tool icon:
3.2.2. Key modifiers (Defaults)
The Shift-b keys will change the active tool to Bucket
toggles the use of BG Color Fill or FG Color Fill on the fly.
toggles the use of Fill Similar Color or Fill Whole Selection on
The available tool options for the Fill Tool can be accessed
double clicking the Fill Tool icon.
The Opacity slider sets the transparency level for the
fill. A higher opacity setting results in a more opaque
fill and a lower setting results in a more transparent fill.
The Mode dropdown list provides a selection of paint
application modes. A list of these modes can be found in the
This dropdown list allows the user to select one of many
fill patterns to use on the next fill operation. The manner
in which the list is presented is controlled by the four
buttons at the bottom of the selector.
GIMP provides three fill types: FG
Color Fill, BG Color Fill and
FG Color Fill sets the fill color to the
currently selected foreground color.
BG Color Fill sets the fill color to the
currently selected background color.
Pattern Fill sets the fill color to the
currently selected pattern.
Fill similar colors
This is the default setting: the tool fills the area with a
color near the pixel onto you have clicked. The color
similarity is defined by a brightness threshold, that you
can set by a value or by a cursor position.
Fill whole selection
This option makes GIMP fill a preexistent selection or the
whole image. A quicker approach to do the same thing could
be to click and drag the foreground, background or pattern
color, leaving it onto the selection.
Finding Similar Colors
Under this section you can find two options:
The option Fill Transparent Areas
offers the possibility of filling areas with low opacity.
The option Sample Merged toggles the
sampling from all layers. If Sample Merged is active, fills
can be made on a lower layer, while the color information
used for threshold checking is located further up. Simply
select the lower level and ensure that a layer above is
visible for color weighting.
The Threshold slider sets the level at which color weights
are measured for fill boundaries. A higher setting will
fill more of a multi colored image and conversely, a lower
setting will fill less area.