What is defined as a mixing system in painting?

The mixing system in painting refers specifically to a setup that facilitates the blending of paint components in precise amounts to achieve a consistent and uniform product. Choosing a answer that describes a mixing rack that activates at a constant rate encapsulates the idea of a designed mechanism that helps automate and standardize the mixing process. This is crucial in achieving accurate color matching and maintaining quality control in the final paint product.

While the other choices may touch on aspects of painting, they do not fundamentally describe a mixing system. For instance, the first option refers to a general blending of colors without specifying the mechanics involved. The option about a machine for applying paint pertains more to the application process rather than the mixing itself. Lastly, the formula for creating custom colors implies a conceptual approach to color formulation rather than detailing the physical process or equipment used to mix those colors effectively. Therefore, the definition that aligns closely with the function and purpose of a mixing system is the one that describes a controlled mixing process.