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!)
Inside the house is where acrylic shines. It dries faster than other types, and it keeps its color better, without yellowing. One disadvantage: It costs more.
Proper rolling technique: When rolling paint on the wall, get the roller skin evenly loaded with paint and make a V,N or M pattern on the wall, this is to spread the paint across the entire section you will be rolling, then roll back across the section and even out the paint. To properly "lay off" each section, make a final pass of the section applying light pressure to the roller frame arm end of the roller skin and bringing the nap mark (mark created on the pressure applied side of roller skin) across from the beginning of the section to the end of the section, and just repeat all the way down the wall.The V,N or M pattern, will be determine by how far the paint will spread, a V is for less spreading paint and M is for farther spreading paints. Do not "dry roll", which means trying to roll to much of a section at once with very little paint on the roller. Just as important, do not apply to much, if you find you are applying to much, increase the size of the section you are painting i.e. from a V pattern to an N or a N pattern to a M.
SECONDARY COLORS. When you mix two primary colors together, you get a secondary color. The secondary colors are orange, green and violet. Orange is made by mixing red with yellow. Green is made by mixing blue and yellow. Violet is made my mixing blue with red.
Take your time there is no rush. There is nothing wrong with having your project take a couple of weeks.
Once you figure out which position is prime and which position is spray, place the valve in the prime position and grab the primer hose. Point the primer hose in the empty bucket near the top and at an aproxx.45 degree angle from the side (the reason for this is that there is likely to be pressure still built up in the airless and when you first switch on the airless to prime it, paint will likely burst out of the primer hose and you don't want to have it go everywhere). Now turn the airless paint sprayer on and you will see that the airless is sucking up the new paint and pumping out the primer hose. At first you will typically see a cleaning solution come out followed by your paint. When you see your paint coming out switch over the primer valve to the other position and you will see the airless pumping paint into the main hose.
Malabar and Designers Guild offer some striking brights while the new Shades of Sanderson comprises 120 colours tailored to Sanderson's collections. If you are aiming for a more subtle backdrop that will flow through several rooms, it's wise to stick to neutral shades. Kevin McCloud's Elements of Colour for Fired Earth works especially well with our cool, northern light.