I used a free online image editing app called Pixlr to achieve this effect, but you can do much the same thing in other software, such as Photoshop or GIMP.
Of course, you don't need to use family photos. We'll even discuss how to insert your family members into exciting action scenes or far-flung landscapes. It's your coloring book, so you can choose the story! Even better, why not let the kids decide?
I'm going to talk through this process in a lot of detail, but that's only so that a complete beginner will feel comfortable. Don't be intimidated by the number of steps; you can actually complete the project in about 5 minutes!
Step 1: Choose a photo
If you're planning to edit any of the people in your photo onto another background, it helps if the original photo is taken against a fairly plain background. For example, you could start by photographing your kids fiercely brandishing toy swords in front of a blank wall, then edit them onto a pirate ship background later!
Save whichever photos you want to use to an easy-to-find file on your computer.
Step 2: Open Pixlr
Pixlr is a free online app that lets you edit photos without having to download any software or pay any fees. It's extremely easy to use, but also sophisticated enough to let you achieve some astonishing photo effects.
Click where it says "Open photo editor" then click on "Open image from computer" and select the photo you want to use.
Step 3: A quick overview of Pixlr's layout
On the right, you'll see a box labelled Navigator. This lets you zoom in and out of the photo and move around when you're zoomed in.
Below that is Layers. This is one of Pixlr's cleverest features. Pixlr lets you stack multiple images on top of each other, then edit them all individually, a bit like making a collage. In this collage, however, you can choose to make the different layers change size, become transparent, or even act as complex filters for the layers below them. Don't worry, we'll come back to that.
Under that is History, which just shows a list of all the recent actions you've performed in Pixlr. If you've made a mistake, you can skip back in your History to before you made it. Think of it as having multiple Undo buttons.
OK, you're now a Pixlr pro! We're all set to get editing!
Step 4: Make it black and white
Step 5: Duplicate the layer
You should now see a new layer called Background copy.
Step 6: Invert the new layer
Step 7: Fancy trickery
At the moment, the layer called Background copy should by in Normal mode. Use the drop-down menu to change it to Add mode. Everything in your image should turn white. Don't panic! That's what we wanted.
Step 8: Blur the top layer
A slider called Amount should appear. Try dragging this back and forth to see what happens. The outline of your image should become visible, starting as a thin tracing when Amount is low and turning into softer, thicker strokes as you increase it.
Adjust the slider to a medium point at which you can clearly tell what the image is, but the lines appear neither pencil-thin nor extremely soft and blurry.
Step 9: Flatten the image
Step 10: Use Levels to adjust the softness
Select Adjustment --> Levels. A graph like this should appear.
Step 11: Move the black slider
Step 12: Move the other sliders
Congratulations! You've made your coloring book image!
Step 13: Save and print
Tips on saving: Sometimes Pixlr will save an image without putting the .jpg extension at the end of it. When you save an image to your computer, quickly try opening it in another window. If you cannot open it, save it again but this time type .jpg at the end of the name.
Step 14: That wasn't so complicated!
Step 15: Advanced lessons
I thought our volunteer enjoy having a thrilling adventure story to color in, so I decided to put him on a desert island with a treasure chest. A quick Google search for beach and treasure chest revealed some useful images, which I saved and opened in Pixlr.
Step 16: Turn your images into outlines
Step 17: Put everything into one image
I then used Edit --> Free Transform to change the sizes and positions of each individual element.
Step 18: Trim the images
Step 19: Choose the final positions
Step 20: Let your imagination run wild!
Try it out and let me know what your kids think!