Rubber-base paints, which dry to a hard semi-gloss finish, may be used on concrete floors below grade, providing the floor is not continually damp from seepage and condensation.
You scuff up existing paint for two reasons. First, you want to get rid of any oil, grease or dirt trapped in the top layer of paint. This is the stuff that cleaners and degreasers can't get off. The second reason to scuff is to set up a physical bond for the new primer and paint to adhere to. You want to give the old paint some tooth so the new sticks better.
To balance color, you must grasp the interconnectedness of color schemes. All color interactions are defined in the color wheel, and it has been used to build color schemes for centuries.
HUE-VALUE-INTENSITY. Hue: Without getting too technical, and to put things into laymen's terms, hue is just another word for color. For instance, grass and leaves are two variations of a green hue.
Remember, you will need to clean the airless in that same fashion before you return the airless back to the rental company.
TEMPERATURE OF COLOR. Colors have temperature, referred to as warm or cool. In painting, reds, yellows and oranges are referred to as warm colors and blues, violets and greens are referred to as cool colors. One of the biggest lessons you will ever learn about color temperature though, is that the appearance of color can change drastically depending on its surroundings. For instance, a certain yellow would appear much hotter if it were surrounded by a violet then say an orange. Another important lesson in color temperature: Warm colors will advance in a painting and cool colors recede.
A large whitewash brush is best for applying the wash. One should not attempt to brush out the coating, as in applying oil paint, but simply spread the whitewash on as evenly and quickly as possible.