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Five Interesting GIMP Filters

The Gimp is a powerful graphical application that can handle just about any kind of bit-mapped editing job. You can re-touch photos, shrink or enlarge pictures, combine elements using layers, and many other operations with little to moderate effort.

The program also has a bunch of interesting “filters” that transform your picture into something new. Perhaps you need to make a cool text logo for your company or are a teacher needing to create some coloring projects, for your kids. The Gimp has you covered in those departments. And, once you try using a few of the filters, I'm sure you'll see opportunities to "filter" pictures, all over the place.

The main portal into filters is found on the main Gimp toolbar, with that name.

Drop-downs are grouped according to the filter effect applied to your graphic. Menu items include distorts, edge-detects, artistic effects, rendering, and so on. Certain menu items have sub-menus, such as, artistic and render. Clicking on a selection typically pops up a window, where you can set various parameters, thereby influencing different aspects of the filter.

If you try a filter and the result isn't exactly what you expected, simply go to the edit menu item on the main tool bar and click undue to remove the filter effects.

Figure 1: The Original PhotoBe aware too, that some filters perform pretty complicated calculations, so a fairly fast processor and ample memory will minimize waiting for the results. All the pictures were processed on an Asus 2.26 GHz, Intel duo-core laptop, with 4 GB of memory and 64-bit Xubuntu. In spite of a stout machine, the emboss effect took about a half a minute, while the old photo effect took about two minutes of processing, even on the performance setting.

Emboss

The emboss filter creates an etched rock picture transformation. Figure 1 shows one of the local buildings in my city. Does anybody recognize the building and location? It's near a famous vacation spot. The picture was taken with a Nikon D80 DSLR camera using an 18-200 mm VR zoom lens and is a 3.2 MB JPEG image. Figure 2 shows the building after running the "emboss" filter.

Load your photo into The Gimp and click on the Filters drop-down menu. Move down to distorts and select emboss. A window will pop up with settings that you can change. If you check the preview box, you can see the effect, before you do any processing.

Figure 2: The Embossed VersionThe emboss filter lets you change azimuth, elevation, and depth. Increasing the azimuth makes the picture look more like a cartoon. Changes in elevation and depth, naturally, affect the chiseling effect.

Jigsaw

Can you see yourself as a jigsaw puzzle. You could process the photo with the jigsaw filter, make an 8 x 10 inch print at the photo shop, glue it to some cardboard, then cut it out. Yes, it's not really that practical. It might be an inexpensive rainy day activity for your kids. They always enjoy doing those kinds of projects. Figure 3 shows your's truly puzzling at lunch.

Click on Filters, then Render, then Pattern, and select the Jigsaw menu item. The pop-up box will allow you to change the number of vertical and horizontal tiles, the bevel around the pieces, and whether the pieces are straight or curved.

Figure 3: The Author In PiecesIf you have a camera with a high pixel count, you can probably blow the image up to a nice size for a puzzle. I'm sure there are other uses for the puzzle filter. Mostly, I think it's just meant for fun.

Lighting

"And the light came down from the heavens." That's my best description of the lighting filter. In Figure 4 you can see how the beam comes down from the upper right hand corner of the photo and shines on the building. You'll probably want to stick with pictures of buildings, portraits, and graphics that have a central focus and high contrast with the background.

Figure 4: Shedding More Light on the Subject.Use Filters, Light and Shadow, then Lighting Effects to call up the pop-up box. A blue dot on the preview screen (inside the pop-up box) lets you move the sunbeam around on the graphic. Left click on the dot and drag it where you want the beam. Moving the dot closer to the edge makes the beam narrower and less bright. The pop-up box has several tabs that change the light source, materials, and other options. Experiment with those settings for the best effect. In the building photo, I originally had the beam streaming down from the upper left hand corner. Looking at the photo I realized that to be realistic, it made sense to move the beam to the upper right corner, because that was the side with the natural light. The left side of the building had the shadows, as seen from my camera vantage point. Study the original photo and you'll see the highlights and glare on the right side.

Old Photo

Did you ever need to make a picture of yourself or a building look very old? Take a look at Figure 5 to see the output of the old-photo filter. It transforms a picture's colors to sepia, reduces the focus, and adds a fuzzy border around the graphic, just like a tattered old photo from the attic.

Go to Filter, click on Decor, then select the Old Photo menu item. The pop up window lets you change the fuzzy border width and whether the processed photo is focused, sepia, or has a mottled look.

Figure 5: Sepia Tones in GIMP.As in the lighting filter, paying close attention to details will help give a realistic effect. For example, if you make our original picture of the big building into an old photo, what are you going to do about the trees, down in front? The filter doesn't magically shrink the trees down to the correct size they would have been 70 years ago. Using the old photo by itself, might be convincing, if your viewer can't see the original, at the same time. For side by side comparison shots, you would certainly need to remove or edit out the trees and bushes, to get a half-way believable old photo. Just something to keep in mind.

Logo

Making a text logo for your company is a little more involved than creating an embossed photo. Don't worry it isn't much harder, just an extra step or two. Insert some text into a new drawing and give it a size of 60 or so. Pick a common font, like Sans. Make sure the text box is highlighted, then click Filters, then Alpha to Logo, and select Chrome. Figure 6 shows the text made out of chrome. Pretty slick, right? I like the Cool Metal and 3D Outline treatments, too.

Figure 6: Create a Cool Logo.There are an absolutely staggering number of combinations and settings that you can apply with the logo filters. And, I'm just talking about a single common text font. Combine the logo filter with different font types, sizes, and colors and you could literally spend months generating new text logos.

Further Filtering

The Gimp has a great online index of all the current filter effects. You can see examples of all the different effects, without having to try each one out on your own photos.

While a lot of people swear by that other program, Photosomething or other, The Gimp has huge array of unusual and interesting features. Filters are an easy way to get great results with just a few mouse clicks.

This e-mail address is being protected from spambots. You need JavaScript enabled to view it is a emerging technology consultant, writer, and portable computing expert. Early adopter tech trends, seminars, and writing projects are his stock-in-trade. His mission is to deliver exceptional value to his clients. Links to many of his articles appear on his Web site at http://home.earthlink.net/~robreilly.

 

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  • Tom Said:

    Excellent! Straight to the point. Great job Rob.


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