Choosing a grout color is never an easy process. There are many different brands and colors of grout to choose from and many people do not know where to begin. Often mistakes are made in picking out the grout or in the actual grout installation process that makes it come out too light. Usually a dark rich color was expected only to find a light colored grout where the color appears to be washed away and dull.
One of the main reasons grout turns out too light is because the wrong color was picked in the first place. Many people go into home improvement stores and look at the color swatches on the boxes of grout and choose a color based on these color swatches. This can lead to picking out an incorrect color which in most cases comes out looking lighter than the color that was expected and wanted. Color swatches on paper often times vary by a huge amount to what the actual color of the grout will be. It is extremely important to use the plastic stick color samples that are supplied by the manufacturers when choosing a grout color. All of the grout manufactures supply these plastic stick color samples but they are usually not available in the big box home improvement stores. It is best to go to a tile store that has these plastic color samples when trying to pick out a grout color.
Another big reason that grout turns out too light is because of the way it was installed. Grout is often mixed with too much water and this will wash out a lot of the colored pigments. Also inexperienced and sloppy tile installers will use too much water when cleaning the grout off of the surface of the tiles. This can also wash a lot of the colored pigments away and give you a washed out light looking color.
Sometimes the wrong brand of grout is used. Certain big box stores grout brands are notorious for looking too light after they are installed. Usually the white colors chosen from the big box stores will have no problems but it is the darker colors that will lose a lot of their color after they are installed. It is best to consult with a professional tile installation contractor or a tile store consultant when choosing a brand of grout. They will have the experience and know how to steer you in the write direction for choosing a quality brand and color that will suit your needs. There are also many newer epoxy and urethane synthetic grouts to choose from that will retain a much richer and fuller color than the normal cement based grouts.