Tutorials - Making Palettes
When you come to think about it, a palette is basically just a gradient with a reduced amount of colours. For this tutorial, we are using a technique on which I came across on DeviantArt for making gradients in MS Paint (There are several tutorials on DA for this, including Etomo's, Meezu's and Xrainfirex's)
Go to Image>Attributes. Set the height to the number of colours you want in your palette (here, 6) and the width to one less than that (so 5).
We're now going to pick the darkest color. Double-click on one of the color spots at the bottom of the program to open the Edit Colors dialog, then click on "Define Custom Color". Use the colour map and the brightness slider to pick a colour that you'll use for the darkest colour of your palette. Try not to pick a colour that is too high up in the colour map, or else it will look very bright and unrealistic. When you're finished, click on "Add custom colors", then on "OK".
Repeat the process for the lightest colour. Double-click on a different spot at the bottom so that you'll still have access to the first colour you picked. Now move the brightness slider upwards until you find a shade that's bright enough for you. The difference between the lightest and darkest colour is up to you, I suggest you experiment so that you can find a good balance. You can also move the crosshair in the colourmap slightly so that the lightest colour is more saturated, or of a slightly different hue. You don't have to do that though if it's not your style. Again, click on "Add custom colors", then on "OK".
Here's where the fun begins. Zoom in to 8x, then select the line tool and the darkest colour that you just made. While holding down SHIFT, draw a diagonal line from the bottom-left to the top-right of the canvas. Since the width is smaller than the height, the line will go one pixel less than the top-right corner. This ensures that the lightest colour that you picked actually gets used.
Flood-fill the bottom-right of the diagonal created with the darkest colour, and the top-left with the lightest colour.
Go to Image > Stretch/Skew, and set the vertical strech to 100.
You now basically have a palette, but it's really tiny. To make it bigger and more usable, go again to Image> Stretch/Skew, and set both the horizontal and vertical stretch to 500%. Repeat the process with 200% stretch if you want your palette to be even bigger (for instance, if you want to put it up on your website.)
Voila! You've got a palette. You can now either save it individually as a bmp, or copy and paste it into another document where you can keep all your palettes for future use.