GIMP for middle school kids (Shallow Thoughts)

Akkana's Musings on Open Source Computing and Technology, Science, and Nature.

Sat, 12 Apr 2008

GIMP for middle school kids

I've been helping out with an extracurricular GIMP class that a local Linux and free software advocate, Christian Einfeldt, has organized at a middle school in San Francisco.

The class meets on a Saturday once or twice a month, so there's plenty of time to forget things between sessions, and most of the kids don't have a lot of prior computer experience (I'm told many of them are behavior problems or otherwise "at risk", but I sure wouldn't have guessed that from their exemplary behavior in class.) Despite the obstacles, the kids have learned some impressive image editing skills in a very short time! Lots of them have figured out how to set their Edubuntu desktop background; I've seen abstract patterns, photographs decorated in various ways (today one girl was painting a mouth, hair and jewelry on a photograph of a chimpanzee's face, and it came out looking very funny), photos of the students themselves pasted into exotic locales, and so on.

It's also an interesting exercise for me in seeing what beginning users find difficult to understand and what aspects of GIMP's user interface are difficult to explain. An additional challenge is that this classroom has no projector or centrally visible screen. So you can't just demonstrate how something works; everything must be explained slowly in words while the students follow along with each step, and then we have to go through the room helping students as they try to remember the steps.

One of the first tasks they take on is combining images: start with a photo of themselves, or of an animal or car, select it and paste it into another image. What's the easiest way of explaining selection of arbitrary shapes? Which method can be explained in less than a minute, and yet they'll remember how to do it after you leave and move on to the next student?

There are three obvious candidates for a general-purpose selection tool: the intelligent scissors, the paths tool, and the quickmask. We had a miscommunication in one of the early classes and didn't discuss which technique to teach, so I taught some students the paths tool while Christian was teaching others the iscissors. I found that both methods had some serious problems.

With Bezier paths, it's easy to click points around your object. Students get a little flustered the first few times they accidentally drag rather than click and drag handles appear, but they can get over that. The part that's difficult comes at the end, where they have to click Path to Selection, then Feather as a separate step (they don't need to feather the first time, but eventually they'll need it). And then there's the problem that the path as well as the selection remains visible, a distraction that they don't understand.

When I saw that Christian had been teaching some students the iscissors while I was teaching others paths, I thought, gee, good idea. Iscissors should be more straightforward, no? Well, no, as it turns out. New students have great difficulty making an iscissors selection. They're fine as long as they're clicking their points; the problem comes when they get to the last point, when in order to make a selection you must click carefully on your first point, then click again inside the figure. A lot of students don't understand this no matter how many times you explain: they don't remember which was their first point (it doesn't look any different from the others), they can't see it anyway (it usually doesn't contrast much with the image), and they can't tell whether they clicked it successfully.

At that point they try to click inside the image and get a spurious extra point -- and then they panic and start clicking all over the place, ending up with a mess that is (as far as I've been able to tell) unrecoverable. The only fix is to toss out that figure and start over, but even that isn't easy to do (click on another tool then back on the iscissors tool button). Basically, the iscissors tool is far too confusing and most students need to be personally walked through it at least three times (some of them a lot more than that) before they get it.

Anyone who's read my writing on GIMP probably knows that I'm a quickmask zealot. I'm a born again quickmask prophet: I used GIMP for years without really understanding the quickmask, and when I finally grokked it, it made a huge difference in ease of selection. I sometimes joke that "the quickmask changed my life", and that's hyperbole, or course; but it sure did change my GIMP editing. People seem to fear the quickmask so I usually don't present it first, but maybe I should. These students are very eager and competent at painting, and I think they'd take to the quickmask very easily with far fewer stumbles than the other two methods have given them.

There's one other variant of shaped selection that I didn't list: the lasso tool in add and subtract mode. The lasso tool is terrifically hard to use to try to select a whole figure from an image. You'd have to have a preternaturally steady hand, plus you can't zoom in and scroll around since the whole figure has to be completed in one movement. But what you can do is make a rough selection with the lasso, understanding that you'll have some errors; then alternate between Add mode and Subtract mode as you use the lasso on smaller areas to get the selection just right. It's nearly as easy as the quickmask, and doesn't require a big conceptual shift. The only reason I'm leery is that I suspect the three modes would confuse a lot of students -- especially since the mode buttons have no labels, merely tooltips.

While I'm on the topic, there's another issue that gives the students trouble besides selection: the floating selection that results from a paste. There's really no way to explain to a schoolkid why it's there (heck, maybe some day someone will explain that to me). And it's useless to try to get them to keep their Layers dialogs visible. (They don't even keep the toolbox visible most of the time; it's always covered by image windows. Most of these Edubuntu machines are working at 800x600 resolution, and there just isn't room on the screen for the normal GIMP window collection.)

So I try to drill them that "Every time you paste, you have to find the Layers window and click that button on the bottom left." Understandably, they often forget that step, then get into trouble because they can't see all their pasted layer, or some functions are greyed out.

Aside from selection and paste, the students seem to cope with GIMP remarkably well. Some of them have been exploring the menus for fun plug-ins, others are trying different patterns to make interesting backgrounds, and one even discovered how to make interesting effects with some of the specialized gradients. At the beginning I wondered if teaching GIMP might not be too ambitious, and maybe something simple like Tux Paint might be better. But GIMP is working out just fine except for those few stumbling blocks. The kids have a refreshing willingness to explore and try things, and the result is a whole lot of really fun images.

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[ 23:44 Apr 12, 2008    More gimp | permalink to this entry | ]

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