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by Eric Lamarque <eric_lamarque/at/yahoo.fr>
About the author:
User of Linux since 1999!
Translated to English by:
Guido Socher <guidoatlinuxfocus.org>
Content:
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GIMP: Make your own brushes
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Abstract:
In this article I will present the various brushes that GIMP offers and
show how to create brushes.
First we will look in detail at the brushes dialog, "Brush
selection", and the different brushes it contains. After that I
will show you how to create your own brushes.
The version of Gimp used for this article is 1.2.3.
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1. The available brushes
First, if you have not done it yet, open the dialog "Brush
selection" (from Menu/File/Dialogs/Brushes). The following
window should appear:
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- Size of the brush: here 13x13
- Name of the brush: Circle Fuzzy (13)
- Current brush
- This small ' + ' indicates that the brush is larger
than shown; press and hold the left mouse button on
these brushes to see them in their real size.
- This small red triangle indicates a, so called,
pipe brush: this brush contains several images
and not only the one shown; click with the left mouse button
on these brushes to see all the images.
- Value of spacing. It is the size of the brush
in percentage (here 25%) which GIMP uses before the
next copy of the image is used. (No panic: you will see
how that works).
Now let us see the various types of brushes. For all the
exercises in this part, open a new image RGB with a white
background.
Reset the colors of foreground (FG) and background (BG)
to black/white. Select the brush "Circle Fuzzy (13)" and
draw a line with the paintbrush tool. Change the color of
foreground to blue and draw a second line.
Impressing!!
It's a
simple brush.
The brush in this case is a grayscale image used by Gimp as an
inverted
alpha channel. The white corresponds to the
transparent color and the levels of gray are used as value
for the foreground color. The file associated to the brush
has the extension ".gbr".
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Set again the colors of foreground and background to
black/white. Select the brush "Vine" from the "Brush
Selection" dialog. Change the foreground color to blue and
draw something.
You note: you wanted vine in blue but it remained green.
"Vine" is a
RGB pipe or
animated brush: it is
not possible to change the color in this type of brush. On
the other hand, the image evolved/moved while you draw. The
associated file type for this brush has the extension
".gih".
Reset the colors of foreground (FG) and background (BG)
to black/white. Select the brush "PencilSketch" and draw.
Change the color of foreground into blue and draw a second
line.
Ah finally! This starts to resemble something!
"PencilSketch" is a
pipe "alpha". In addition to
drawing with the color of foreground, the brush changes
during the drawing. The file type associated with this
brush has also the extension".gih".
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Change "Spacing": Reset the colors of foreground (FG)
and background (BG) to black/white. Select the brush
"Circle(13)", set spacing to 20% and draw a line.
Set spacing to 100% and draw a second line.
Set spacing to 200% and draw a third line.
This experiment shows the influence of spacing on the
brushes. For decorative brushes ("Guitar "or" Pepper"), one
will generally choose a spacing of 100%.
2. Creation of a simple brush
Reset the colors of foreground (FG) and
background (BG) to black/white. Open a new image
(File->New) with image
type gray and fill type
background.
Trick: Do not hesitate to create an image larger
than the size of the desired brush: it is easier to work on
a big image and then reduce than to make the brush in
real size.
For the example, the image with a size of 256x256 and will
be reduced to 64x64.
And now, using some imagination, you just have to create
the brush of your dreams.
For the example, I drew a boat.
Trick: If you want to obtain a brush with soft
contours, use the filters "Blur" from the right click
menu.
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[
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Here an outline of my example already reduced to 64x64.
If you think of modifying/reusing the elements of your image
later on, it is the moment to save now as .xcf or
never come
back : the creation of the brush is an operation with a
single direction. Once the file ".gbr" is generated, one loses
the original elements of the work in progress (path,
channels...).
Now to finally create the brush do this:
- if your image contains more than one layer, transform it
so that it has only one layer and flatten the image
(layers->flatten).
- if need be, scale the image to the final size of the
brush. In the example, the image is reduced to 64x64 (right click
image->Image->Scale Image).
- save your image with the extension ".gbr" in the
directory ~/.gimp-1.2/brushes/. In the example, the file is
called "bateau.gbr".
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- give your brush a name and choose spacing (percentage).
These parameters will appear in the dialog "Brush
Selection". Here, the brush will be named "bateau" (French
for boat).
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And ready is the magnificent and
decorative brush. But it does not appear in the dialog
"Brush Selection". Press the refresh button and it becomes
available.
You can now use your brush.
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3. Creation of a RGB pipe
A pipe - or animated brush - is a brush
which contains several images. The image of the brush
varies at the same time as one draws: it is the experiment
we did with the brush "Vine" in the first part.
In GIMP, the creation of a brush of this type is an image
with several layers.
NOTE: Only the brush "pipe" can have colors (RGB).
If you want a fixed brush color (like "Pepper"), you will
have to create a pipe with only one layer.
This is what you do: create a new image
RGB with
"fill type"
transparent.
Hint: Do not hesitate to create an image larger than
the size of the desired brush: it is easier to work on a
big image and then to reduce than to make the brush in the
final size.
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Remove the layer which is by default there. It is called
"Background".
And here we are, using our imagination, we just have to create
the brush of our dreams.. For that, create a layer with a
"transparent fill type" for each image of the future brush.
For the example, I used my image of the boat with 3 different
colors.
Important: All the copies must contain a alpha channel.
The simplest way to do this is to create the copies with a
transparent background ("Fill Type=transparent").
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Your master piece is ready. Here a
screenshot of the layers from the example: a boat with 3
colors.
If you think of wanting to modify/re-using the elements of
your image later on, then save it now as .xcf : the
creation of the brush is an operation with single
direction. Once the file "gih" is generated, one loses the
original elements of the work in progress (layer, path,
channels...).
Now to finally create the brush do this:
- if need be, scale the image to the final size of the
brush e.g 64x64 (right click->Image->Scale
Image).
- save your image with the extension ".gih" in the
directory ~/.gimp-1.2/brushes/. In the example, the file is
called "bateau.gih".
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-
The dialog to create a pipe has a lot of possibilities.
For clearness of the article, I will just focus on the
simple case:
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- Enter the spacing in percentage
- The name of the brush as it should appear in
the "selection of brushes" dialog.
- Ranks: this parameter must correspond to the
number of layers present in the brush (4 layers in
the example).
- Selection: it is the order in which the
layer(copies) of the brush are used. In the
example, "incremental" will produce the image "Deep
Blue" then "Blue" then "Blue blade" then "Deep
Blue"... The other modes which are easy to use are
"angular" and "random".
It is done: now you have a new animated
brush. But it does not appear in the dialog "selection of
brushes" until you press the refresh button.
You can now use your brush.
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4. Creation of an "Alpha" pipe
A "alpha" pipe is an animated brush which
contains several images of the type grayscale. The brush
"PencilSketch" is of this type.
In GIMP, we need to create an image with multiple layers
and image type "Grayscale".
Reset the colors of foreground (FG) and background (BG) to
black/white. Create a new image of type "Grayscale" and set
fill type to "Background".
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Remove the layer which is by default there. It is called
"Background".
And here we are, using our imagination. I drew for example a
simplified face.
IMPORTANT: No layer must have any transparent
pixels. The easiest way to achieve this is to create all layers
with the fill type "background".
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The master piece is ready: four different
expressions of a face.
If you think of modifying/reusing the elements of your
image later on, it is the moment to save now as .xcf or
never come back : the creation of the brush is an
operation with a single direction. Once the file ".gih" is
generated, one loses the original elements of the work in
progress (path, channels...).
Now to finally create the brush do this:
- If need be, scale the image to the final size of the
brush. In the example, the image is reduced to 64x64 (right click
->Image->Scale Image).
- Save your image with the extension ".gih" in the
directory ~/.gimp-1.2/brushes/. In the example, the file is
called "faces.gih".
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-
The dialog to create a pipe has a lot of possibilities.
For clearness of the article, I will again focus on the
simple case:
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- Enter the spacing in percentage
- The name of the brush as it should appear in
the "selection of brushes" dialog.
- Ranks: this parameter must correspond to the
number of layers present in the brush (3 layers in
the example).
- Selection: it is the order in which the
layer(copies) of the brush are used.
It is done: now you have a new animated
brush. But it does not appear in the dialog "selection of
brushes" until you press the refresh button.
You can now use your brush.
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[
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5. Importing of brushes from Paint Shop Pro
There are a lot of brushes available for Paint Shop Pro
(extension "tub" or "psp") and it may be that you find one
which correspond to your needs.
- Check first of all that the conditions/license to use the
brush are compatible with your project.
- Simply open it in GIMP: if this fails, then the format is
unknown because the file was created with a too recent
version of Paint Shop Pro. No chance.
- When brush is open in GIMP; save it with the extension
"gih". The majority of the parameters are already correct
just set the name of the brush and the spacing.
- Move the brush image to the directory
~/.gimp-1.2/brushes/. Press the refresh button in the dialog
"selection of brushes".
Let's try and example from
graphicssoft.about.com, the
site of Sue Chastain.
This site has the advantage of providing good information for
each brush: note it down for later use.
Brush "Translucent Colored Orb Tubes" (file sc-colororb.tub):
- "Total Cells 8": the pipe contains 8 images
- "Cells Across 4, Cells Down 2": lines in 4 columns and 2
rows
- "Step Size 150": spacing with 150 pixels
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Open the file in GIMP. Even if the
extension ".tub" is not mentioned explicitly in the type of
files, the format Paint Shop Pro ("PSP") is supported.
You should now have an image containing
eight bubbles colored on a transparent background.
Save the image under the name "sc-colororb.gih".
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I marked in red circles on the left side the fields you
need to modify:
- Spacing: 150 pixels. With the bubbles having a size
of of 146x150, we can assume that it will be 100% (a
full bubble).
- The name of the brush: SC (the initials of the
author - rather widespread convention) and some
meaningful name.
Notice that GIMP automatically filled the number of cells
(8) and the way of finding them in the image ("2 Rows of
4 Columns ": 2 lines out of 4 columns).
The number of rows and the selection are also converted
(8 rows - angular selection).
Save the file with these settings and copy
sc-colororb.gih to ~/.gimp-1.2/brushes/.
In the dialog "Selection of brushes", use the button
"refresh" and your new brush is accessible.
You can now use your brush.
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6. Conclusion
Now, you know almost everything about brushes. But for what
can that be useful? Here some examples:
One can also create brushes to change photographs, to add
texture to parts of an image and probably plenty of other uses.
Now, with your brushes!
References/Links
Note: The tutorials ones on mmmaybe.gimp.org will
change URL at the time of the redesign of the www.gimp.org
site: mmmaybe.gimp.org will become www.gimp.org.
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2003年10月10日, generated by lfparser version 2.38