In my own research of the movies before and now, I noticed that the old animated movies don’t have much shadings on the character. Background and props are usually painted in details. Disney movies for example, the characters don’t really have much shadings in them, the shadings are used when there’s an intense lighting or a way to show atmosphere of the scene. From Snow White to Princess and the Frog, the shades are either not used or very light in most of the time.
Disney studio are releasing 3D animation more often than 2D animation. I heard that is because 3D animation is more profitable than 2D animation. There’s a kind of shader in 3D programs has been developed in this 10 years – Cel-shading or Toon Shader. It is a very simple shader. It applies flat shadows onto the models, with the settings it provides, texture packs and lighting effects, a 3D animation is created quicker than before. This is why the number of production of 3D animation has significantly grown recently. Toon shader is inspired by the shades from old cartoons. This is a way to create consistent frames. Simple shading can tell stories and environment clearly, it can be drawn very easily too thus a convenient way to create consistented animations. Most of the cartoony animated films are made with toon shader but it is not visible due to the large amount of lighting, VFX and filters covered onto the scene.
Here is some examples of toon shader as you can see they are very simple and easy to render. Take Pokemon (pokemon go as well) as an example, they are the perfect example of toon shader. All of the pokemons are covered with simple shades am a little lighting.

