I will show you three techniques for re-coloring elements, beginning with the simplest case and moving on from there.
As a review, you'll need Gimp installed and running, and if you're a newbie to digital editors, you should go through my earlier tutorials first as I assume familiarity with several tools.
I am recoloring elements from the Oopsie Daisy collection downloaded from digiscrapobsession.com (for free, of course!)
We'll be using the following tools and techniques:
1) The Colorize command
2) The Scissors Select tool
3) The Circle Select tool
4) The Select-By-Color tool
Let's talk about the limitations of the techniques I'll be covering first, though:
* The easiest elements to recolor are monochromatic to begin with - that is, they consist of black, white, and various shades of a single color.
* You cannot typically change a bright white embellishment to deep purple. Nor can you change a black embellishment to light pink. For the most part, the original "lightness" or "darkness" of your embellishment can be tweaked only a little before the results start to look highly unnatural. Also, the Colorize tool we'll be using simply isn't designed to work on pictures that are mostly all white or all black.
* Complicated elements containing many colors, very irregular shapes, etc. are very difficult to recolor successfully- unless you can be content with a monochromatic result!
That said, we still have a lot of latitude available to us. Let's take a look at a simple example.
Example One: Recoloring an entire embellishment
1) Open the bow element that you'd like to recolor
2) We need to find the color we'd like to change it to. My general technique is to use the color dropper tool to select a color from my page layout - probably one of the major colors from the background paper. (To get to the color dropper tool, click on the Foreground Color in the tools palate which brings up a pop-up dialog. The color dropper is the icon next to the HTML notation box about half-way down on the right.)
Once you have the color you want selected in the Change Foreground Color dialog, the important step is to memorize (or copy down) the numbers that appear in the "H" and "S" boxes (for "Hue" and "Saturation.") In this case, 336 and 51
3) Now select Color->Colorize from the menu. Your element immediately turns a bright shade of aqua and a dialog appears with three sliders, one each for Hue, Saturation, and Lightness.
Input the numbers you copied from the Color dialog into the first two slider boxes.
You'll see your embellishment change color in sync.
The "Lightness" value is one you'll just have to play with by eye. It entirely depends on the original color of your embellishment whether you'll just leave the value default, or adjust it upwards or downwards by 10 to 30 points. In my case, I adjusted the lightness downwards by 20 points.
That's all there is to it! Your green bow is now deep purple!
Let's move on to a more complicated scenario
Example Two: Recoloring a portion of an embellishment
1. If you're following along with the Oopsie Daisy collection, open the silver brad with the purple center. We're going to change it from purple to moss green.
2. Use the color dialog and color dropper tool to find a nice shade of green as in Step 2 above and note the H and S numbers.
3. As in step 3 above, use the Colorize command to change everything to green.
Wait... that doesn't really look right! We'd much rather retain the nice silver setting for our embellishment, and change just the center to green.
4. Use the Circle Select tool on the tools palate to select Only the center of the brad.
Tips: Checkmark the "Expand from Center" option, and also checkmark the Fixed:aspect ratio option. Enter 1:1 (for a perfect circle). You may also wish to check the "feather edges" option, which gives your final selection a soft edge. A value of around 10 for feathering should be sufficient.
5. Now, go back and do step 3 again.
This time only the center of the embellishment changes color.
From here the tutorial is really just exploring different means of selecting the precise portions of the embellishment you want to change.
Example Three: Using the Scissor Select tool to eliminate portions of the embellishment from recoloring
1. Open the light blue button with white thread in the center.
Although as I mentioned above elements that are mostly white do not recolor very well, if you simply use the Colorize dialog on this element, the white thread will take on a purplish cast which is not entirely desirable.
2. Use the Scissor Select tool to select only the thread portion
"Scissor Select" is a really powerful tool that automatically detects edges in your image and snaps its selection to those edges. It definitely takes some practice to use well!
I refer you to this tutorial for in-depth information on how to use the thing.
The basic technique, however, isn't too complicated. Left-click on the image where you want to start "clipping" along the edge of the white thread. Then click several more times around the perimeter of the thread. Think of it like a dot-to-dot: you're placing the "dots" around the edge of the thread, and the scissor select tool is connecting them - it's just being smart enough to follow the contour of thread when it does. Where practice is required is getting the interval between your dots right - close enough that the tool can "guess" what you're trying to select accurately, but far enough apart that you yourself don't do 98% of the work.
When you've completed your perimeter, join the first dot to the last dot by clicking that last dot and either click inside the curve, or hit enter to convert your clipping to a standard selection.
3. Once you've successfully selected the thread, choose Select->Invert or Cntrl-I to invert the selection (because we want to change the color of the button, not the thread!) If you did not checkmark the "Feather Edges" option when using the Scissor Select tool, you may also want to choose Select->Feather and chose a relatively small value like 3 to 6. This will make the boundary between the recolored and original pixels soft and add to the realism.
Now, use the Colorize command as in Step 3 in the first example.
If you successfully selected the thread, you should get a nice purple button with bright white thread in the center.
There are several other methods available for selection portions of embellishments for recoloring. I occasionally use the Select By Color tool, for instance, when the portion of the element that I do Not wish to change is too complicated to select via the Scissor Select tool. However, I am typically Least successful when I use this technique. Regardless of tweaking, I still always end up selecting too much or too little, and the end result looks blocky and unnatural.
I've had better success with this tool when recoloring background papers that are already a bit fuzzy and imprecise to begin with.