Oil stays a long time wet with other words a slow-drying paint, therefore it gives you more control over the paint. This paint consists of particles of pigment suspended in a drying oil, commonly linseed oil. The stickiness of the paint can be modified by the addition of turpentine or white spirit. To make it more gloss you can add varnish on the painting when done. Oil paint was commonly used to protect the wood in buildings and exposed metal structures such as ships and bridges.
Oil painting is to most forgiving medium because it gives you more time to make corrections. You can work wet on wet over a long period.
Oil painting can be complex like in math or it can be super simple. Some of the old masters let it look very complex but it is actually very simple.
Oil paint is not toxic. It exists out of oil and pigment. The oil in the paint is the vehicle or binder. The most commonly used vehicle is cold-pressed linseed oil, walnut oil, poppy seed oil or safflower oil. Paint dries through a combination of the oxidization and evaporation. The rate of evaporation of volatile compounds will depend on atmospheric pressure, temperature, and humidity. Lower pressure, higher temperature, and lower humidity will all increase the rate of evaporation of the solvent. The linseed oil and pigments oxidize (react with oxygen) and harden, but the oil has a low enough vapor pressure that it doesn’t appreciably evaporate. Cross-linking occurs between the relatively small oil molecules, essentially forming a plastic. The hardening process takes place in the first few hours/day/months after the paint has been deposited, but the process never really stops.
The process never really stopping is why you shouldn’t varnish an oil painting as soon as it’s touch dry but should wait several months. The less time the oil paint has to spend “drying”, the more likely your varnish is too crack.
It is not safe if you swallow it. Tinners are toxic so it is important to paint in a well-ventilated room.