What is the difference between a grout stain or dye and grout colorant or grout paint?

In essence these three products are all very similar. However, a grout stain or dye is used to darken the existing grout where as a grout colorant or grout paint can either make it lighter or darker. If for instance, you have a light grout that you just can seem to keep clean, you may want to apply a grout stain to darken it up a bit. A grout stain blends the existing color of the grout with the stain rather then replacing it. I will generally only change the color of the grout slightly.

Grout stains and dye are slightly hard to apply then grout paint or a grout colorant. One on the major advantages is that they stain can soak in a little further.
Before applying a grout colorant, be sure to use a grout cleaner to clean of the area completely. You may also want to take a brunch and clean out the grout. Be sure to remove any loose material out of the grout. After you have cleaned it, make sure it is completely dry. It might be best to wait a few hours before applying the grout colorant or paint.

Pour the paint into a shallow container. Using a small brush, paint the grout from the middle outwards. Be sure to keep the painting as clean and as neat as possible. It you get any of the grout paint of colorant on the side, try to clean it up quickly with a damp rag.

After the first application allow the colorant 4 to 5 hours to dry. Then apply the second coat using the same techniques you did with the first. After that let it dry for 24 hours before walking on it again.

The first step in choosing a grout paint or colorant, is to find the color you want. It can be either darker or light. Generally people lighten grout to restore it to its original color. Occasionally they may also darken it in order to make grout stain less visible and make maintenance easier. The advantage of painting is that it can revive your grout without all the hard work involve with rerouting or replacing all the existing tile. Compared to re grouting, painting your grout is only about one tenth of the work. As long as your tile and grout are in good condition, this is the process I would most recommend.