The material. Some coloring books offer the ability for the child to simply run over the surface with the pens or crayons provided, and it will turn out to be the right color regardless. Some are more like paint books, and some have magic marker surfaces and come with markers that will not show up on any surface but the specially prepared book pages. Choose the book that best suits you and your child. If you are worried about markings on the walls, then dont select a pack of basic crayons, get something that uses special crayons. If you want your child to exercise their own creativity and not have to fit in the lines or color schemes planned, get basic pages. It is up to you.
I know that in this era, computers and gadgets are really booming and bombarding every home. The majority of the parents cant catch up with the inclination but through uncomplicated things like coloring books, for sure, kids can have a superb time with their parents. There are also free coloring online materials and games that you can make use of while bonding with your kids.