Property:Development:Construction:Painting

Primer: a coat put on to materials (generally porous ones such as concrete/drywall/wood) before painting. Because primers do not need to be engineered to form a durable finished surface, they are engineered instead for improved filling and material binding properties. Priming can also diminish the amount of paint needed.
- Sanding before priming improves adhesion, as well as remove staining if any¹⁾.
- Priming can raise the grain of wood it is applied to, therefore post-priming sanding with a fine grain (to leave the primer intact²⁾) is recommended, especially if you want a high gloss (non-dull) finish.
- Primers are usually chosen to be tinted, which may reduce the number of paint coats.
Paint: after sanding, applying a primer, and re-sanding it, you can apply a coloured finish intended to protect the material from the elements.
- There's a specific window in which to apply paint to the primer. Usually painters apply paint before the primer is still cured³⁾).
Self-Priming Paint: promises to do both steps in one go, saving time (but not expense as it is more expensive) – but is really not much more than “thicker paint”⁴⁾.