DECORATIVE AND COLORED PLASTERS
Another way to create a unique look on your finished wall is to use colored or decorative plaster. Colored or decorative plaster is what we call a finish that has mineral colors added to it. It allows the applicator to create many unique and beautiful effects. However, before you choose this option, you should be aware of all of its advantages and disadvantages.
The first important advantage of colored plaster is that it is cost effective. It is fairly inexpensive to finish and it eliminates the need to paint. It is like combining two jobs into one. In addition, you eliminate the hours that would have been spent actually painting the room, speeding up the time before the room can be occupied. Another benefit of adding colorant to the final plaster finish (as opposed to painting) is that it allows the lime in the plaster to age longer. This creates a stronger, harder finish. The reason for this is that lime continues to strengthen when exposed to the air. The longer you put off painting the more beneficial it is to the life of the plaster. Painting too soon can retard the hardening of the lime. However, this does not mean you have to be stuck with one color forever. You can always paint the walls later when they become dirty and need updating. A third advantage is the versatility of the finished look. For example, up to three colors can be added to the plaster to give it a unique blended or marbleized appearance. Also, you can obtain a spattered effect by spattering color over a fresh putty coat. The final advantage of using colored plaster is that, unlike painted plaster, it will not show a different color when scratched. Although you want to avoid scratching any finished surface, a scratched painted wall, in particular, will show the lighter plaster underneath rather than conceal it. On the other hand, a scratch on colored plaster goes unnoticed because the finish is a single, homogenous, colored layer.
The first disadvantage is unwanted color variation on the wall. The applicator needs to make sure to maintain the same color throughout the project. This is achieved only by adding the exact same amount of water and color to the dry material for each batch. In other words, inaccurate measuring (a common error in the field) can lead to variations in color. It is also important to use only a high quality mineral color that is resistant to lime. One way to eliminate color variations is to use manufacturer-prepared color finishes, but these are generally more expensive than adding the color yourself. Another disadvantage to using a colored plaster finish can be found in its application. In order to avoid unwanted visible joints (which are caused by breaks in the application process), you must complete the entire wall in one go. Therefore, it is important to have sufficient material on hand and enough extra manpower to cover the wall at one time. A final disadvantage to colored plaster is in its upkeep. Fingerprints, whether left by children or other tradesman on the job, can be difficult or even impossible to remove from the wall once they are there. One possible solution to this problem is to sandpaper the offending prints off the wall. However, you must be careful not to damage the wall in the process.