I don't know about everyone else but, I think its hard to find tutorials for anything other than Photoshop. Not to knock Photoshop or anything. Photoshop is really nice if you can cough up the money for it. So I went the less expensive route.
With just a few easy steps I will show you how to use the clone tool to add color to a black and white photo.
Be sure to save your photo under a new name so that you don't mess up your original.
What you will need:
1. The latest version of GIMP. http://www.gimp.org/
2. A color photo
3. Steady mouse hand
Step 1: Start Gimp and Desaturate
Then open a color photo of your choice. Be sure to "Save as" before you modify the photo. I named my photo "flowerblackandwhite" Once opened, select "Colors" from the drop down menu and choose "Desaturate". This will convert your photo into shades of gray.
Step 2: Open a Second Copy of Photo
Step 3: Selecting the Source to Clone From
Then press and hold down the "Ctrl" button and select an area on the color photo that will be easy to find on your black and white copy. This area should be in a spot you would like to add color to your black and white copy.
I always try to find a spot in the photo that is easy to pick out so that I will have a good reference point to start from for the next step.
Step 4: Using the Clone Tool
Now go to the same exact spot on this photo that you selected in the color photo. Click and hold down the left mouse button and use it like you would with the paint tool. I try to go around the edges of the object I want to colorize first just in case I have to start over.
If you don't start at the same spot you selected in the color photo it will not align properly and you will have to undo and try again until you find the right spot. This is not always easy.
Step 5: Touching Up the Edges
Goto your color photo and "dsaturate" the image. Then hold down the "Ctrl" button to select a new area. This area should be outside of the place you colorized in the black and white photo.
Now go back to the photo where you were over on the edges and find the new spot that you just selected on the color image. Then begin to touch up the edges just like you were doing before but, now your taking the color out.
Step 6: All Finished
Have fun with this.
Please if you have any questions or tips, feel free to comment. I am by no means a professional in photo editing but, if you have trouble getting any of this to work please let me know and I will do my best to help you any way I can. Thank you for viewing my Instrucable, please don't forget to vote