hpr-knowledge-base/hpr_transcripts/hpr3150.txt

Episode: 3150
Title: HPR3150: GIMP: Paint Tools
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr3150/hpr3150.mp3
Transcribed: 2025-10-24 17:49:13

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This is Hacker Public Radio Episode 3,150 for Friday 28 August 2020. Today's show is entitled,
Gimp Pain Tools, and is part of the series Gimp. It is hosted by Ahuka and is about 18 minutes long
and carries a clean flag. The summary is with paint tools you begin to operate on the image.
This episode of HPR is brought to you by archive.org. Support universal access to all knowledge
by heading over to archive.org forward slash donate.
Hello, this is Ahuka welcoming you to Hacker Public Radio and another exciting episode
in my ongoing series on Gimp. I should just mention something to level set what's going on here
and that is I am using Gimp 2.8 on Kabuntu Linux 1804.LTS. I mention that because it is not
the the current bleeding edge of things. I think Gimp is now 2.10 is the current.
But it hasn't been offered up by my repository yet and probably part of the reason is I'm working
on a two-year-old version of the operating system. There's a reason for that. It's an LTS release
and I stick with LTS releases. And the reason is that some years ago I got very tired of working
on my computer and now I only work with my computer. So what I expect is probably going to happen
is that I will be offered the next LTS version which would be 2004. Probably within a month or two
would be my guess. Usually it comes out in you know towards the end of summer because with LTS
releases they kind of wait until you at least get the .1 service pack before they
offer to upgrade all the LTS installations. And chances are when that happens I'll probably be
able to upgrade to Gimp 2.10. But you know be that as it may I don't think that's really going to
have a huge effect on what we're doing here. This is a product that's been around for a long time.
And I think most of what it will do is pretty well established. Now I want to take another group
of tools this time and that is the paint tools. And that's another big group of tools and this is
towards the bottom of the the tool section of the sidebar. You know with the selection tools
you're at the top these are at the bottom and then next time we'll get to the transform tools
and so on. So the paint tools you'll see there are 13 of them and the first one looks like a paint
bucket. Well that's kind of a pretty good clue as to what's going on. Now in the standard install
you'd see them at the bottom. Now they can also be found by going to the tools menu.
And note that if you move your cursor over an icon the tool tip will pop up and give you the name.
All but one of them also has a keyboard shortcut if you're into that sort of thing.
Now what are they? Well there's bucket fill which has the shortcut key of shift B. Blend which
is the shortcut key of L, pencil which is a shortcut key of N, paintbrush with a shortcut key of P,
eraser, shortcut shift plus E, airbrush, shortcut A, ink, shortcut K, clone, shortcut C,
heal, shortcut H, perspective clone. This one does not have a shortcut key but I suspect it's
because it's not something you do all that often. There's a blur sharpen which has a shortcut of
shift plus U, smudge, shortcut key of S, and dodge slash burn, shortcut key of shift plus D.
Now basically all of these tools they're called paint tools because you basically use them by
dragging a cursor around like a paintbrush. And as we saw at the selection tools every tool has
specific properties down in the bottom the options that you can select that appear when the tool is
selected. Now to be clear drawing with a mouse cursor is not going to work well in a lot of cases.
If you'd be doing a lot of that kind of work you'd probably be better off investing in a tablet
and stylus which give you much better control over your drawing. But if you only need to do occasional
quick and dirty stuff a mouse can work if you're careful and there are some aids for example trying to
draw a straight line with just the mouse cursor will never look very good. But if you hold down the
shift key you can click on the beginning point of a line, hold with the shift key hold down,
go then to the end point of the line, and gimbal draw straight line between the two points and
you'll be able to see it. If you do the same thing we did last time you know open up a blank canvas
as we discussed in the last episode by going to file new, you can practice this stuff. Good idea
to do that and what you'll see is that if you're doing this right when you hold down the shift key
and start clicking what's going to happen is there'll be a plus sign at the beginning of the line
and another plus sign under the cursor as you move it to the other end of the line and the straight
line connecting them. So you'll be able to see very easily what's going on. So once you do that you
can then just keep holding down the shift key and keep clicking and you'll get a connected series
of straight lines. So that that can be pretty handy and if you hold down control and shift you'll
get what's called a constrained straight line and what that means is it will constrain the line
to the nearest multiple of 15 degrees. Now this is great for getting perfectly vertical horizontal
or diagonal lines. Now another concept to keep in mind here are foreground and background colors.
Now just below the tools section on the sidebar you will see two overlapping rectangles
with the top one covering part of the bottom one. The top one shows the foreground color which
will probably be black if you haven't changed it and the bottom one shows the background color which
will probably be white if you haven't changed it. Now if you click on one of the rectangles you
can change the color. Now this matters because the paint tools generally use the foreground color
for drawing. So being able to get the color you want is very helpful.
Now a brief look at the tools. Now bear in mind each tool has many optional property settings
that fine tune what they do. I won't go into all of the details here but in the show notes I've
put a link to the online GIMP documentation. So if you want a lot more information on any of these
that's where you should go to get it. Now they have a documentation that covers different
release versions so I'm linking to the 2.8 because that's what I'm using. If you're using 2.10
you know it's just to change one number in the URL and you'll get there as well.
So what are these tools? Bucket fill, Shift plus B. Now what this does is it fills an area with the
current foreground color. But if you hold down the control key while clicking it fills it with the
background color. So either one is available to you depending on using a keyboard selector there.
So yeah pretty simple you select a color you select an area and you know the area gets filled with
the color. Blend which is shortcut key of L. This fills a selected area with a gradient blend of
the foreground and background colors. So a gradient means it's going to gradually shift from
one color to the other. So you know as you move from left to right on the left will be the foreground
color and then as you move to the right less and less of the foreground color is there and more
and more of the background color comes through. Now you have two main areas of selection here. The
gradient itself and then there's also shape. So you can create gradients that are linear,
which would be what I just described. But you can also have gradients that are circular and
conical and you know you can take a look at all the different options there.
Pencil, shortcut key of end. This tool and the paintbrush tool are similar. Differing mostly in that
the pencil lines have hard edges and the paintbrush tool has fuzzy edges. Hard edges are good when
you need a high degree of precision. To get a straight line click the beginning of the line then
hold down the shift key and click the end point of the line. By default the line will be in the
foreground color. You can use the background color though by holding down the control key
or if you like you can switch the colors around. If you take a look at those overlapping rectangles on
the left sidebar and you look in the just the upper right of where those two rectangles are there's
a double arrow head. One arrow pointing horizontally the other arrow pointing vertically down and if
you click that it swaps the positions of foreground and the colors of foreground and background.
Background will now become foreground, foreground when I'll become background.
Paintbrush. Similar to the pencil except that the line is a bit fuzzier on the edges.
But this is a good opportunity to point out you can select different brushes to use for both
this tool and the pencil tool by going to the brushes section on the bottom of the right sidebar.
We'll talk about brushes a little bit more later. It certainly deserves at least an episode
in itself but I just mentioned it here because you do have some options. Now the eraser shift plus E
as you would expect erases or removes color from an area.
The result will be either the background color coming through or if there's an alpha channel
some transparency will show up. Now transparency and gimp is indicated by a grayscale checkerboard pattern.
And what that means is that when the image is finally rendered you won't see anything
where there is that transparency.
So this can be useful particularly if you're working with masking layers. And again layers
is something we haven't talked about yet. Hold your horses and we're going to get there.
This is the part that is probably least interesting. It's just going through all of the different
things you can do. It should be more fun when we get to actually looking at doing things.
Now the next tool is the airbrush. And the airbrush is for painting soft areas and it works
by making the painting lighter. So as an example if the foreground color is red and you select the
airbrush tool and draw a line it'll paint something closer to pink. You know just a lighter shade.
The ink tool shortcut K. This tool imitates a pen and it can be used to create calligraphy effects.
Now you would have to experiment a little to see how it works but as with a pen you can control
things like the size of the nib and the angle at which it is applied.
Clone tool shortcut C. This tool lets you copy from an existing image or pattern.
It is used a lot in repairing photos for instance where you can paint over an artifact in the
image with nearby pixels that were unaffected but it can also copy patterns.
Note that if you're trying to copy from an image that has multiple layers you need to select the
layer first by holding down the control key and clicking on that layer.
The heel tool is next and the heel tool is related to the clone tool but is perhaps more powerful
for small changes at least. And not only copies pixels over but also takes into account through
a clever algorithm of the area surrounding the target. This can help for example in removing
wrinkles from photographs. Now perspective clone. Perspective is based on the idea of vanishing lines
one of the great breakthroughs of Renaissance painting which is to draw the line showing how things
further away from you seem to get smaller and closer to each other because of the distance.
Think about what happens if you're looking down a railroad track. It might be perfectly straight
and they might be perfectly parallel but they give the impression that the rails are somehow
approach each other as you go further down the tracks. So it's just a visual
you know the way we see things when we're looking. So to use the perspective clone tool you start
by drawing the vanishing lines and then clone an image that will get smaller as it goes into the
distance and if you keep adding clones they also get closer together in the distance.
Now the in the gimp documentation the example they give is an image of a road that you might create
and think about that road having dashed white lines down the center. Well perspective clone would
let you create those dashed white lines as clones of the original one and the further you go the
smaller and closer together they seem to be. And that's what it would look like if you were looking
at such a road. Now the blur sharpen tool shift plus you. This tool can either blur part of an
image or sharpen part of an image. Each pass of the cursor adds a little more effect.
So this can be useful for adding something to a small portion of an image.
But if you want to affect the entire image there are filters that are really much better suited
to that task. Now you can switch between blur and sharpen by holding the control key.
Smudge shortcut ks. This tool does what it says. So let's imagine you were going to write something
an anchor paint something and then rubbed your thumb across it while the anchor paint was still wet.
Well what would happen you would get a smudge wouldn't you? This tool emulates that as you move
the cursor across it picks up color and starts mixing it in as you move the cursor.
So as you drag it across the image you're going to get that kind of effect.
And finally the dodge slash burn tool shortcut key shift D. This tool is used to lighten or darken
pixels in an image. Now you can switch between lighten and darken with the control key.
There's also a range selector in the properties area that will restrict the tool to affecting only the
darkest areas, shadows, midtones or lightest areas highlights. You can see how this might be useful
for photo retouching. So in summary, very brief introduction to the various painting tools in
Gimp. As with the selection tools I advise a little play and practice to see how each of these
works. Create a white canvas and start drawing on it. Create free form lines, straight locked
and constrained lines and see how the brush selections affect things. And with that this is
Ahuka for Hacker Public Radio signing off and advising you as always to support free software.
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