Like this, it will actually take quite a while to reach a number that is close enough to the yellow color you've chosen that you can't tell any difference (and mathematically, you will never actually reach an average of 4!)
What colors are prevailing - tonal or local, warm or cold?
Proper brush technique: When "cutting in" with a paint brush you should dip the brush in paint and tap the sides of the bucket on each side of the brush, leaving a good amount on the brush so you are able to minimize the times you will need to dip/load the brush. Next, take the brush and make a one foot to two foot line down the wall about an inch or two away from the trim or surface you are going to paint up next to, this is much like taking a knife full of butter and spreading it across an entire slice of bread. After, spreading the paint over the section, go back and even the paint out evenly across the section and cut up next to the trim with the brush. You want to paint up next to the trim or surfaced to be cut-in with the paint brush after you have released most of the paint on the wall, it is easier to cut in with the tips of the brush exposed and not loaded with a lot of paint.
Concrete Floors. Two general types of paints for concrete floors are varnish and rubber-base paint. Each has its limitations and the finish cannot be patched without the patched area showing through. Floor and deck enamel of the varnish type gives good service on concrete floors above grade where there is no moisture present.
Again, as with Warm and Cool, hair is the most important characteristic in determining Light or Deep. Women with Light coloring tend to have blond, light brown, or light red hair. Women with Deep coloring tend to have brunette, dark red, or black hair.
Some manufacturers recommend their vinyl paints for interior as well as exterior use; others say no, not so good. There are vinyls made specifically for interiors.
Now that you have primed the airless, make sure that there isn't a tip in the gun of the airless and bring it over to the empty bucket. Since there is typically cleaning solution in the hose leading to the gun it is a good idea to spray that out until you see thick paint coming out. Once you have thick paint coming out you may put your tip back in. Remember that the tip will have an arrow on one side of the handle that shows which direction it must be in, in order to spray.