Episode: 3190
Title: HPR3190: GIMP Brushes
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr3190/hpr3190.mp3
Transcribed: 2025-10-24 18:29:33

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This is Hacker Public Radio Episode 3190 for Friday 23 October 2020. Today's show is entitled,
Gimp Brushes,
and as part of the series Gimp, it is hosted by Ahuka
and is about 20 minutes long
and carries a clean flag. The summary is, paint tools
and particularly the paintbrush tool. Require the use of brushes.
This episode of HPR is brought to you by archive.org.
Support universal access to all knowledge
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Music
Hello, this is Ahuka, welcoming you to Hacker Public Radio
and another exciting episode in my ongoing Gimp series.
Today I want to take a look at brushes.
When we looked at tools, we looked at paint tools
as one of the categories of tools.
The thing about paint tools is that you need to use them with a brush
for the tool to be usable. So it seems like a good time to take a look at brushes.
Now, all of the paint tools, except the ink tool,
use the same set of brushes, though generally you use them with the paintbrush tool.
Try using brushes with a few different tools and you soon realize
they don't always work well with other tools
and depends a bit on the brush and all of that.
But Gimp comes with a default set of brushes
but because it's open, you can add brushes as well.
Brushes are technically something called PixMaps,
which is short for pixel maps.
And they have a definition, link in the show notes, as always,
that says a PixMap stores and displays a graphical image
as a rectangular array of pixel color values.
So what are the key things here?
We're talking about pixels.
Generally, we're talking about raster. There's also vector.
And we're going to look at both a little bit.
It's rectangular.
So it doesn't have to be a square necessarily,
but like all of the things you work with in a program like this,
it is embedded in a rectangular grid.
And it has color values.
Oftentimes those colors are black and white,
but it depends on the brush. They don't have to be.
Now, if you're going to use built-in brushes
or ones that other people have already created,
maybe the definition of things doesn't matter.
But it's worth noting you do have the ability to create your own.
And I'm going to look at a few examples of that.
But in more general terms, Gimp is written in the C programming language.
And there's a standard method in C for creating PixMaps.
I'm not going to get into that. This is not supposed to be that technical editorial.
So I'm just going to mention, if you want to do some web searching,
there's lots of references out there, and I've put one of them into the show notes.
Now, when you're working with brushes, you're going to work with the brushes dialog.
And that is found on the lower right, if you have anchored everything,
which is what I always do.
It'll be on the right sidebar at the bottom.
And it has various options for selecting.
And at the top, there are three tabs.
The first tab is brushes, and that's by default what you're going to have opened.
But there's also patterns and gradients.
I'm probably going to talk a little bit about those in the next tutorial.
So with the brushes tab selected, that's what we're going to go forward.
Now, let me just mention, in essence, what you have here is three dialogues.
If you click the Patterns tab, you're in the Patterns dialog.
Click the Gradient tab, you're in the Gradient dialog.
But they all work pretty similarly.
And for each tab, there are configuration options.
There's a tiny little button on the far right of the tabs,
which looks like a leftward pointing arrowhead.
And this gives you a few options.
One of the ones I would recommend, particularly if you're just getting started with this stuff,
is to go into those options and select View as List instead of View as Grid.
Now, the Grid display is what you would get by default when you install the program.
But when you view as List, you get additional information that I think is a little helpful
in getting to know your brushes.
So it's going to give you the name of the brush.
It's going to give you the dimensions of the brush.
Remember that it's rectangular.
Many of them are square, but they don't have to be.
So if you get that additional information,
I think it's going to make up a little easier for you to get to know your brushes
and understand how they work.
Now remember, all brushes are just rectangular bit mapped images
that you apply with your mouse or other pointing device.
Now, I say other pointing device.
For certain things, you know, using a pen with like a pet tablet
is probably going to give you your best results.
Drawing things with a mouse is frequently a somewhat chancy operation.
Anyway, under the tabs, there's a drop down that says Filter very faintly until you've used it.
But once you've used the Filter function, that goes away.
And you'll either see the name of the filter that has been employed or you'll see a blank space.
Now, what Filter lets you do is view brushes of a particular type.
You saw among the built-in ones.
You're going to see categories like basic, legacy, media, sketch, and so on.
You'll also see the brushes in sets that you might have added that are listed in here.
So, let's say you went to DeviantArt, which is a website,
that I recommend you check out if you're interested in any of this stuff.
You know, you can download a whole set of brushes from DeviantArt,
and they'll come with a name, and you can take a look at that.
For instance, in an image that I published on my website, showing all of this,
there's a collection called Micro Patterns that I downloaded from DeviantArt,
and you can see each of the brushes listed with that name on them,
and Micro Patterns 1, Micro Patterns 2, and so on.
So, that's stuff that I've added to my collection.
Now, following this gallery of actual...
You know, following this dropdown is the gallery of actual brushes for you to look at.
Now, if you double-click on one, it opens the editor.
But note that brushes that come with Gimp by default, many of those are not editable,
and most likely the ones you download from sites like DeviantArt are locked and not editable.
But any that you create can be edited by you,
or for the ones that come with Gimp, you can open them in the editor,
then make a copy and edit that copy if they are parametric.
Now, I'm going to get into that in a little bit here when I talk about adding brushes and editing and things.
Now, under this gallery of brushes is the spacing setting.
Now, this affects what happens when you click and drag the paintbrush tool with this particular brush.
When you click and drag, you are setting down a series of images which will overlap.
I think of it as like your stamping, and sometimes the stamps are almost on top of each other,
or sometimes they are next to each other.
And that's all controlled by spacing.
And now, the spacing is done with a number that is defined as the percentage of the brush width.
So, if it's set to 100%, there will be no overlap at all.
The different images that you stamp in there are stamped next to each other with no overlap.
And so, you'll have distinct images pasted.
If it's less than 100, there will be some overlap and you'll get some kind of continuous line,
depending on what sort of brush you've selected.
Now, at the very bottom is a row of icons in order.
Edit this brush, create new brush, duplicate this brush, delete this brush, and refresh brushes.
Selecting edit, create, or duplicate, all of those will open the brush editor.
But for the ones that are locked, you won't be able to edit unless you are working on a copy.
Now, adding brushes.
If you want some good additions, I've got some links in the show notes, some sites you can check out.
Now, I've already mentioned DeviantArt and some of these web pages that I'm referencing go back to DeviantArt as well.
But you might want to go to one of these websites because of the curation aspect.
Instead of searching through the gazillion different things available on DeviantArt,
one has presumably taken a look at some and said, hey, these are really good.
So, among these sites, there's like best gimp brushes for drawing and painting, all free.
Seven must have gimp brushes, free download, the 20 best gimp brushes, the best free brushes for gimp in 2020.
11 free gimp brushes and how to install them, which is actually pretty darn simple.
Gimp brushes, in general, are going to come in three file formats.
There's the GBR format.
Now, GBR is also used for something entirely different, but, you know, how many three-letter file format designators are there.
But in this case, it's a gimp brush format, and it's used for ordinary and color brushes.
G-I-H is for animated brushes with images from multiple layers, and then there's VBR, which is a vector brush format,
and like all vector images, it can be resized without loss of clarity.
Now, brushes are simply files that you store in your brushes directory.
So, take a look in GIMP, and under the GIMP directory, you should see a brushes directory,
and that is your personal brushes directory.
The ones that are built into GIMP are not there.
However, any that you create or any that you download, all you have to do is just put them in that directory.
Just copy the file and put it in there.
So, I mentioned deviant art. You can find just about anything there.
It's free to join, and you can participate in the community.
If you download a brush from there, it will come in a zip file, and you can extract that into your brushes directory.
You can make it easier to keep track of things by extracting into subfolders, which is fine.
GIMP will find them. No problem.
And once extracted, you need to go into GIMP and use that refresh brushes that I mentioned, which is on the bottom of the brush dialog.
And with GIMP 8, that looks like the two arrows in a circle.
And once you click that, the brushes will show up in your brushes dialog.
Now, what if you want to create new brushes?
Several ways to do that, either starting from scratch by making a copy of an existing brush and editing that copy,
or copying all are part of an existing image.
Now, brushes that are parametric can be edited by using the parameters in the brush editor.
Now, this means they are not raster based, but vector based, and can be resized without losing any clarity, which is useful.
Non-parametric brushes are those that are purely bitmaps, and are such are more advanced topic, I won't cover.
Although, you know, GIMP is a raster based editing tool. Just thought I'd mention that.
Now, the easiest thing to do is start with an existing brush and make a copy.
So, I did an example of this, and you can see it on my webpage with a nice parametric brush called Star.
A nice 5-pointed star. Cool.
Well, to edit it, first you double-click to open it in the editor, then make a copy using the copy this brush icon on the bottom.
The editor will now say star copy.
Now, this can be edited by changing the parameters, first the shape.
Right now, the diamond shape is selected.
If you select instead the circle, you'll get a star that is kind of rounded.
And if you select square, it will look almost like kind of a broken down box with square things sticking out from the center.
Now, there are other parameters. There's radius. That changes the size of it. Very simple. Spikes.
Spikes determines the number of points on the star.
So, if you wanted a 6-pointed star, like a star of David, just change it from 5 to 6. There you go.
Now, if you've selected a square shape, and then you go to the spikes and change that setting, that changes the number of sides.
And so, you can get various polygons if you want to get a pentagon, a hexagon, what have you.
By selecting the correct number.
Now, hardness determines the amount of feathering on the border. If it's extremely hard, there's no feathering at all.
It just goes from black to white.
But if you take the hardness down a little bit, you get a little bit of feathering. Or a lot, if you want.
Now, aspect ratio is the ratio of width to height. Remember that all of these things are rectangular images.
Even if what you see doesn't look like a rectangle, what you see is located within a rectangle.
And so, the aspect ratio affects the dimensions. And if you increase it, that basically flattens the image.
Because it makes it wider than it is tall. Angle rotates the image.
So, if you wanted to do an upside down star, rotate it until it's pointing down. Spacing.
Now, as we saw before, we talked about this, drawing a line with the paintbrush essentially stamps a sequence of images onto the canvas.
Set this to a low number. And you got a solid line. Increase it. And you get distinct images.
Now, that's what happens when you edit an existing star image, for instance.
Creating a new brush is a similar process, except that Gimp chooses to start you with a small fuzzy round shape.
But, you know, you can start manipulating that. If you don't want it to be fuzzy, you can start affecting the hardness.
If you don't want it to be round, you can select a square or a star, a square or a diamond instead of a round thing, and so on.
So, you really do have control here. Now, finally, whenever you copy something to the clipboard in Gimp,
it also appears as a brush until you put something else on the clipboard and then whatever else you put on the clipboard appears as a brush.
So, these are very ephemeral. They don't last. If you close Gimp, it all disappears. But, suppose you want to keep one of those as a brush.
Well, you can save the image as a brush by going to edit and then going to paste as and then select new brush.
Now, of course, since this is an image that you've copied onto the clipboard, it is rasterized.
So, it's not parametric. You cannot edit it the way you do parametric brushes. But, of course, as a rasterized image, you can edit it in Gimp before you save it.
Now, using brushes, to use a brush, just select the paint tool you want to use, usually the paint brush, then click on the brush you want to use in the brushes dialog.
Now, I think it would be exceedingly tedious to go through each and every one of these. What I suggest you do is just open a blank canvas, you know, like a 1920 by 1080 with a white background color,
and start selecting different brushes with the paint brush tool and just start drawing different things on there and see what they can do.
That's really the best way to get a feel for this stuff.
So, you know, if you do a single mouse click, you'll put a single instance of that brush on there. It's an image.
If you click and drag, you'll get some kind of a line and, you know, be like placing a whole bunch of the picks maps in a line.
A bear in mind the picks map itself is just another image. This means you can be playful with brushes. You'll see some of the built in ones.
One of them is called green pepper, and another one is tulip, and there's simply images of a green pepper or a tulip, which you could place in any other image.
Now, also note, you can use brushes with the eraser tool. And in that case, you're just doing the reverse. You're erasing something instead of adding something.
Well, this has been a look at the brushes, and this is a hookah for Hacker Public Radio signing off. And as always, encouraging you to support free software. Bye-bye.
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