With the paintbrush or pen tool, you can draw a straight line, at any angle (not just 45/90/180) by clicking where you want the line to start, holding down Shift, then clicking where you want it to end.
Take a look at the this image. Let's say you want to get rid of the sky, or change it to a different color, because you're going to just use the mountains in a separate image. You want to get rid of that shape of blue; however, there could be bits of blue in the shadows that you don't want to get rid of.
Now look at this; you want to do something similar, select a bunch of one color, but you want all the instances of that color.
For the first instance you use the Fuzzy Select tool; for the second you use the Color Select tool.
Using each of them is simple. Click on the tool, then set the tolerance threshold and any other options.
Click in the image; you'll see what's selected. If you're happy, press Delete or complete another task on the selected area. If not, click off and reset the threshold or other settings.
There's a pre-fab redeye reduction filter in GIMP that works pretty well. Here's how to use it.
1. Open the image with the red eye issue.
2. Click the rectangle select tool. You’re going to select the area of just the eyes. You don’t have to do this but if there is red anywhere else in the photo, you risk having that turn darker too unless you select just the eye portion.
Draw a box around the eyes.
3. Choose Filters > Enhance > Red Eye Removal.
In the window that appears, check to see in the preview area if the red is still visible. If not you're fine; if so you need to increase the tolerance, i.e. the amount of color similar to red that’s changed.
If the eyes are red, drag the slider bar to the right. Stop when you see that in the preview area the eyes are now dark.
In my enthusiasm to share GIMP tips, I forgot to back up and talk about it a bit.
It's an open source program for editing and creating raster images. So, Photoshop like. It's not Photoshop lite, though; as with Photoshop there are hundreds of features that I've never heard of the words for, much less know how to tackle. It's big and powerful. I am not a graphic artist so can't do a detailed evaluation or comparison, but my point is, it's got lots of stuff.
"GIMP is an acronym for GNU Image Manipulation Program. It
is a freely distributed program for such tasks
as photo retouching, image composition and image authoring.
It has many capabilities. It
can be used as a simple paint program, an expert quality photo retouching
program, an online batch processing system, a mass production image
renderer, an image format converter, etc.
GIMP is expandable and extensible. It is designed to be
augmented with plug-ins and extensions to do just about anything. The
advanced scripting interface allows everything from the simplest task to
the most complex image manipulation procedures to be easily scripted.
GIMP is written and developed under X11 on UNIX
platforms. But basically the same code also runs on
MS Windows and
Mac OS X."
Here's what it looks like.
I definitely recommend downloading it and trying it out. You might have heard that it's hard to use. I wouldn't really say that. Some of the items aren't under the menu you'd expect them in, and the phrasing is a little weird, but overall, not too bad. Plus, I'm blogging about it here for a while, and there'll be a book coming soon.
You can get a screen shot of your whole screen at any time by pressing Print Screen. You can also use Snagit, which I personally love. However, if you'd like to do screen shots with GIMP, here's how.
1. Get ready to take the shot, then choose File > Create > Screen Shot.
2. Choose to grab a single window. Also, if you need some time after grabbing the window to do stuff, specify a delay. For instance, you might want to click on a window, then start a video, or select some text, or something else that can't be done while clicking on the window you want. (Some quick keys or cursor capture stuff is hard to do without a delay.)
3. Click Grab.
4. Drag the actual little crosshairs to the window you want. You don't see it here but when you do drag the crosshairs, a darker black border will appear around the selected window.
5. A new untitled document will appear, containing a screen shot of the selected window.
I've been playing (and writing a book about) GIMP for the past month or so and if you've been thinking about getting started, I definitely recommend it. I'm not a graphic designer so the advanced stuff is beyond me in experience/application, but I use Photoshop and everything I do is doable in GIMP. Some of it seemed easier (some not) to my self-taught Photoshop mind.
Here's a simple but not obvious basic. When you copy an image and create a new empty document in Photoshop, it automatically reads the clipboard and creates on in the appropriate size. In GIMP, it proposes standard 600x400 or something static like that.
How do you get GIMP to give you the right size for your copied image automatically? Choose File > Create > From Clipboardinstead of File > New.