Episode: 3095
Title: HPR3095: Intro to GIMP
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr3095/hpr3095.mp3
Transcribed: 2025-10-24 16:38:41

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This is Hacker Public Radio Episode 3,095 for Friday 12 June 2020.
Today's show is entitled Intro to Gimp. It is hosted by Ahuka
and is about 18 minutes long and carries a clean flag. The summer is
an introduction to Gimp to kick off a new series.
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. And I am now going to start looking at
something called Gimp which stands for the Gnu image manipulation program.
And it's often referred to as the open source equivalent to Photoshop.
It is a raster based program meaning that it operates on individual pixels.
So does Photoshop. And this is distinct from what we call vector based
programs which operate on lines and curves
described by equations. The example of that in open source world might be
inkscape or in the proprietary world Adobe Illustrator.
Now photos are inherently pixel based so a raster based program is the appropriate
tool generally speaking for working on photos.
Little fun fact Photoshop originated in the area I live in as it began with the
University of Michigan graduate student. And I live here because I went to the
University of Michigan as a graduate student and just never left the area.
So what started me on this was that I have a lot of old photos that I've been
taking a look at that my wife and I have they go back to the 60s and 70s and
some of them are in pretty rough shape. I'd like to see if I can fix
some of these so I thought well you know this is an opportunity to
learn what I can of Gimp but while the photos are my primary interest I'll
take a look at the program more generally. Now to do that I need to find some
resources. Well in this day and age that's pretty easy.
YouTube has some good ones to start with and I've got links to all of these
in the show notes and anyone who has followed my programs may have discovered
by now I tend to have reasonably detailed show notes for
things you can look up online. So here's some some YouTube ones
good ones to start with how to use Gimp Beginners Guide,
how to use Gimp Basics, Gimp in less than 10 minutes
beginner's guide, Gimp Tutorial, Top 5 Photo Enhancement Techniques,
and there's other things. There's the online you've got the Gimp.org
Tutorials site, an introduction to Gimp Photo Editing Nine Things You Need
to Know, how to use Gimp 20 Gimp 2.10 Tutorials for Beginners from the
Davies Media Design Company, Gimp Basics, Best Tips and Tricks for Beginners
from PC World, how to Gimp Tutorials for Gimp and Photoshop.
So you has a lot of stuff there. So that's going to be where I start from
and maybe I'll say something that will get you interested and
you'll want to go beyond what I do in these simple tutorials to start with.
Now the thing about software tutorials when you're searching online,
I always tell people to be careful about when they were written and for which
version of the software. A five year old tutorial may no longer reflect how the
software works now. So if you stumble across this particular tutorial a few
years from now, you should be just a bit wary. There are tons of resources here
and that's a good thing but you know make sure you get the right resources.
Now one of the things I want to mention as well, Gimp Magazine, which looks like it has
stopped publishing, they did put out 12 issues before they stopped and it looks like they are
still available from an organization called Issue.com, ISSUU. Now again link in the show notes.
They had 12 of these things there about five years old. So based on what I just said to you,
you might find some interesting stuff that just be careful. Things might have changed a little bit.
So let's say you've decided, ah, interesting idea. I should try this Gimp thing
that Hooker is talking about. Well step one is install the software.
Now I'm on Linux and some distros of Linux may have this included automatically,
but I just checked and I have a number of graphics programs installed, but when I looked I did not
have Gimp installed. Well there is a downloads page at Gimp.org and it correctly spotted that I'm
using Linux and offered me suitable packages, but I find it's much better to work with my
package manager for my distro. And I've got a good package manager installed.
If you're not using Linux, I will just mention in passing, they have installation files for OSX
and Windows as well. But on my Linux distro, I prefer Synaptic, so I just opened it up by
installing Gimp. I also made sure to install some additional help files that are in English.
There's files in other languages as well, quite a few of them really. So
after doing all of that, I had Gimp 2.8.22 installed onto my Kabuntu 18.04 box,
which is what it will be until they decide to push me to the 20.04. I like to stay with long-term
support releases. As I mentioned before, I'm at the point in my life. I don't want to work on my
computer. I want to work with my computer. So something that makes things easy is good.
Now, upon opening Gimp, there is something a little disconcerting to me at least.
Instead of being a single program window, it opens several disconnected windows, laid over whatever
program was already open. That's not something I am used to. So instead, I looked at the central
window where I had the usual menus and clicked on the Windows menu and selected Single Window
mode. Now, as my investigations move forward, I may become convinced I should switch back,
but I'm very used to each program having one big window.
Now, with that single window, there are five sections. The toolbox, which is on the upper left,
tool options, which is on the lower left, the canvas, which is in the middle, layers, channels,
pads, and undo, which is in the upper right, brushes, patterns, and gradients, which is on the
lower right. So those are your five main sections. Now, the first section toolbox can be further
broken down into various kinds of tools. The selection tools include rectangle, ellipse,
free select, fuzzy select, select by color, scissors select, and foreground select.
Generally, the first step in most operations in Gimp will be to select the objects you're
going to manipulate. So you'll use the selection tools a lot, and they are the first of the tools
to show up in the toolbox. They let you select the area of your image that you want to work on and
let you make changes there. Note that when you mouse over any of the icons, you will get a tool tip
that describes what it is. Then, down at the bottom of the group are the various paint tools. Bucket
fill, blend, pencil, paintbrush, eraser, airbrush, ink, clone healing, perspective clone,
blur sharpen, smudge, and dodge burn. Then in the middle of the window are the transform tools.
Move alignment, crop, rotate, scale, shear, perspective, flip, and cage.
Then the rather miscellaneous tools. One that looks like a capital A is the text tool. Let's
you draw a text box and put text into it. And between the select and the transform group, you will
find paths, color, picker, zoom, and measure. Now again, this is for my installed version 2.8.2.2.
If you have a different version, you may have slightly different tools, although almost all of them
should be the same, regardless of version. Now, tool options are below the toolbox,
and they give you additional control over whichever tool you have selected. You click on a tool
to select it, and then the tool option panel will display relevant options you have. For example,
if you select rectangular select as your tool, you will get options like replace, add, subtract,
and intersect. And then you can add things like rounded corners to your selection.
But if you had picked, say, the pencil tool, you would get options like opacity, brush size,
pencil hardness. So the options you get are appropriately matched to the tool.
Now, if you take a look at the upper right layers up here there, and they are very important.
Gimp operates on layers, and an image can have many layers while you were working on it.
You can think of this like a stack of transparencies with each transparency holding an object of
some kind. That could be an image, a text box, a colored oval, or any of the many things Gimp can produce.
You need to get in the mental space of using layers proficiently if you're going to be a good
user of Gimp. This is also true of Photoshop, but I am sticking to open source here.
To work with layers, make sure that you have selected the Layers tab, which is in the top left
of that window. In the Layers channel's paths undo window, and that window itself is in the upper
right of your screen. So with the Layers tab selected, you can then add layers as needed.
There is a Add New Layer on the bottom left of that window, and build up your image gradually.
One of the great advantages of this approach is that you can easily change your mind on something
by just removing a layer. If you decide you don't like what it did. This is like a gazillion
times better than using undo. Believe me, Control Z is in my genetic code by now,
because I use it so often. But this is better. You can, for instance, remove a layer that maybe you
did a week ago, and there are five other layers that you've added since on top of it.
Well, you can just go back and pick that one layer, and get rid of that.
And then all of the more recent ones are still there, just fine. With the undo, that's not
an easy thing to accomplish. So we'll get into layers in much more detail later on.
But for now, let's just say this is a key concept in working with Gimp.
Of course, finished images do not in our experience come in layers.
So this brings us to another key concept, the working file. When you're working in Gimp,
you are building a working file. This is, again, similar to Photoshop. A Photoshop native file has a
.psd extension, while the Gimp native file has a .xcf extension. And I looked that up
and what is .com gave me this information.
Xcf is a file extension for an image file native to Gimp. Xcf stands for Experimental Computing
Facility. Similar to a Photoshop document, PSD. Xcf files support saving layers,
channels, transparency, paths, and guides. Yet don't support saving the undo history.
Xcf files are supported in other image editors. Yet due to how often the Xcf format is revised,
it isn't recommended for use as a data interchange format. On a side note, the name Xcf honors
the Gimp's origin at the Experimental Computing Facility of the University of California,
Berkeley. And I've put again a link in the show notes if you want to find where I got that.
So what this means in practice is that as you are working on the image, you can save it,
and you will have an Xcf file. This file can be worked on until the image is complete.
And at that point, you would export the image as an image file like, for instance, a JPEG,
a GIF, a PNG, or any of the other image formats that you happen to prefer.
Now note that if you later want to make changes, the exported image file no longer remembers
any of the things like layers, channels, and so on. But if you have saved your Xcf file,
you can open that up and make any changes you wish.
So it's a good idea to save your Xcf file often and keep it around for future use.
One idea is to have two directories, or directory trees, if that's how you roll,
one for the Xcf working files, the other for exported finished files.
And you probably want to get used to saving often as you work, since a crash can cause you
to lose all of your unsaved work. GIMP does not, at this point, have auto-save capability.
So far as I know, there is a script available as a plugin, and I've put a link to that in the
show notes. If you're the sort of person who wants to go down that path, I have not learned
how to do plugins in GIMP yet. I'll probably get there at some point when I do. I'll do a tutorial
about that. But if you're more advanced than I am, it's written in Python, it's at Github,
and the link is there, so you can check it out. Now, just to level set all of this, I
I think I've said a few things already that would have given you the impression that I am not
the world's foremost authority on this. This is more a case of me documenting as I learn and
sharing that with the HPR community. Please do not consider me the last word on any of this stuff.
There's probably lots of people that know more than I do about this. I just haven't seen
anyone do anything on HPR about it, and I thought, well, I can do that. I'm going to do a number
of shows that are essentially tutorials, and those of you who have been around for a long time
may remember the Libre Office tutorials I did. I guess the idea is to try and do something like that
with GIMP, and we'll see where that goes. This is Huka for Hacker Public Radio. I am going to
sign off now, and as always, remind you to support FreeSoftware. Bye-bye!
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