I spent several hours today working with the Gimp software application today, mostly doing work in trying to create textured areas, canvas backgrounds, and irregular lines (like chalk lines), and I'm writing this post for myself so I can remember everything I tried, and specifically what worked.
I think I've written this before, but to draw a straight line in Gimp:
To create a straight line that looks like a chalk line:
To make the line even different, you can "Apply jitter" to your line. (You can see these effects in the image I just shared down below.)
There are several things you can do to vary your line thickness while drawing. Under Brush Dynamics within the Pencil and Paint tools:
I assume that last setting works if you have a digitizing tablet, but I didn't have one today.
When you need a really large/wide Gimp brush, you can:
I've been using Gimp for a long time, and had no idea how to create a large Gimp brush size like this until I stumbled on this feature by accident today. (It feels weird to choose a brush size, then scale it.)
The easiest way to create a textured background is with the Gimp Canvas filter:
Another easy way to create a textured background is with the Gimp Bucket Fill tool:
Another way to create a textured background:
You can use the Gimp Clothify artistic setting to create a textured background:
3, BlurY3, Azimuth
360, Elevation90, Depth=1, but you can vary these as desired to get different effects.
This tends to give your background a little bit of a "leather" feel to it and make it a little darker. I've only tried this with a few colors, so I imagine these settings will have to change a lot for different colors.
You can also just use a textured background in a selected area. Use one of the three selection tools -- including the Lasso Tool for irregular areas, then use one of the methods shown above.
There are many other textured background approaches you can take with Gimp, including using the Gimpressionist tool (Filters, Artistic, Gimpressionist):
For each of these, make sure you click Apply, then Update in the Preview area to save yourself some time. Also make sure you press Reset, unless you want to combine effects.
You can also combine these effects with Paper and Brush settings:
Be sure to adjust the Scale and Relief settings to see how those work.
As one quick example of an image with a textured background and black, chalky lines, here's an image I created as an exercise today:
You may not be able to see it in this small image, but in the larger image -- and more importantly the printed image -- you can see the textured background as desired.
You can also use many other Gimp effects after selecting an area with the selection tools, including but not limited to:
Have you ever seen those cool designs where there is something like a light-green text used on a dark green background, and wondered how they blended those colors so well?
There are at least two ways to do this. First, you choose a great foreground color to match your background color. Maybe that's what the great designers do.
Second, you can:
With this approach your white font gains as much of the background color as you want it to. Of course you can leave it as all white for bold designs, but for cool designs, let some of that background color come through your letters, and your text will blend in naturally.
There are a lot of ways to use Gimp to create a cartoon from a photograph of yourself or anyone else, but the approach I prefer is:
With this technique you're creating a sketch of yourself on the transparent layer. You'll also want to create a plain white layer, and put it between your photo and your transparent layer. You can then enable the white layer to see what you've sketched, and disable the white layer to see your lines sketched over your photo. (You can do this very easily in the Layers Dialog.)
Some people may not like that approach because it's a manual process, but I've created several excellent sketches of relatives this way, and they keep asking me for more.
I hope this collection of Gimp textured background and line tips has been helpful. It's an unusual article in that I normally try to focus on one topic, but I wanted to make sure I had notes of everything I tried today.