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.
EXTERIOR PAINTING. In buying paints that you are going to use for your exterior house, you have to pick a brand that has essential characteristics: hiding power, color retention, chalk-resistance, and blister resistance.
Acrylic is the second new name for magic in paints. This is also a plastic-in-water. Solid acrylic you know as the beautiful, glasslike Plexiglas and Lucite.
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.
Alkyd is an old interior paint made newly popular by a change in solvent - a super-refined petroleum chemical that has almost no odor. It is not a water paint. You thin it and clean brushes with mineral spirits or turpentine, or, if you want to retain the odorless feature, with the new odorless solvent. (Ask the paint-store man for just that, odorless solvent).
Since the trim is the first to go, the main body of the home will be shortly behind requiring painting. If the trim was recently painted, and a few years later the body is ready for paint, all the trim will need to be covered, commonly referred to as masking off. Masking off expends time, labor and material, which adds to the bottom line cost to the remaining 40%, typically costing an additional 25% for masking trim. Thus costing 25% more after both trim and body portions are painted in separate years.
THE STYLE / MOVEMENT. The fastest way to interpret a painting is to determine what movement it belongs to, or at least what movements and styles influenced the artist. The style influences the choice and treatment of the subject, the color, the perspective and the symbols. Impressionists, for instance, experimented with unusual perspectives - bird's eye or frog's eye; their brushwork is visible and the colors are laid separately to mix in the eye of the viewer rather than on the palette. In impressionism the light is more important than the people it bounces off - quite different from romanticism. In romanticism you have to be a poet, a revolutionary, a gypsy or a vagabond to make your way into the painting - they appreciated the bold spirit, the freedom and the people who were different.