How do you dye an egg?

The dyes generally used for making pysanky are aniline dyes. These are, chemically speaking, acid dyes, meaning that they work best in a mildly acidic environment. The dye binds to the protein portion of the eggshell. To get maximal binding, you need to do two things: 1) acidify the dye solution and 2) allow the dye molecules enough time to bind. We acidify the solution by putting vinegar in it. Follow directions, though--too much of a good thing is not always, as Mae West noted, wonderful. Too acid a solution, and the calcium carbonate portion of the eggshell will dissolve. This will weaken the shell and may even destroy its bond to the outer protein cuticle. As for time--that takes patience. Leave your egg in the dye until you get the color you want. I would not, though leave it in more than an hour or so--at that point the dye can begin to seep under the wax. Keep in mind that some eggs just don't have very good shells, and nothing you do will make them take dye well. Sadly, this is something you won't discover until after you've already put a lot of work into an egg.