You have a greater tool - your PC - that can be helpful to get the printouts of diverse colorful sheets. Guide the children, exclusively during the holidays to add illustrations to the colorful-page, and showcase them around the prominent places of the house. This will give them, a sense of pride and joy for their creativity, and would lead to further productive pursuits. Thus, you will witness that there are massive advantages of coloring-page relatively to coloring books. Coloring sheet are economical, costing you only a couple of cents in ink and paper rather than a few dollars for a coloring book.
While coloring pages may seem simple in the minds of parents and other adults these days, they are often the passport into a more creative style of play. Yes, your child will simply color the picture online, but by doing so, she is learning not only to stay inside the lines, but to balance color and texture and to simply use her imagination. If a coloring page for kids is the first step into a full-fledged imagination based entertainment package, it is unlikely many parents will find them simple for long.
This will help them to not only recognize different colors but to also learn the names of the different colors. Developing these skills will help in later development too as your child begins to learn to read and write. He or she can then learn how to write the names of all of the different colors. You see learning is progressive and incremental - it happens in stages. Step-by-step as I have described. This is the true beauty of learning...the more that your child puts in, the more they will get out of learning. As their knowledge grows, so will their interest in a range of different subjects.