Color theory is the study of how colors interact with each other and the effect they have on the human eye and mind. In modern oil painting, color theory plays a crucial role in creating visually appealing and harmonious compositions.
There are several key concepts in color theory that are particularly relevant to oil painting. These include the following:

Hue: Hue refers to the pure color of a pigment, such as red, blue, or yellow. In oil painting, artists often use a limited palette of colors, mixing them together to create a wide range of hues.
Value: Value refers to the relative lightness or darkness of a color. In oil painting, artists can create different values by mixing a color with white or black.
Saturation: Saturation refers to the intensity or purity of a color. In oil painting, artists can create different levels of saturation by mixing a color with a complementary color or by diluting it with a medium or solvent.
Temperature: Temperature refers to the perceived warmth or coolness of a color. In oil painting, warm colors such as reds, yellows, and oranges can create a sense of energy and vibrancy, while cool colors such as blues, greens, and purples can create a sense of calm and tranquility.

By understanding these concepts, artists can create visually pleasing and harmonious compositions. For example, they can use complementary colors (colors opposite each other on the color wheel) to create contrast and balance, or they can use analogous colors (colors next to each other on the color wheel) to create a sense of harmony and unity. They can also use techniques such as color mixing, layering, and glazing to create subtle variations in color and texture. Overall, color theory is an essential tool for modern oil painters, helping them to create expressive and impactful works of art.

How To Ignore It:

While color theory is an important aspect of my art, I and other contemporary artists choose to disregard it as a deliberate creative decision. Here are some ways an artists like myself, do it:
Experimentation: An artist (Brian Drake for example) I may choose to experiment with unconventional color combinations or use colors that are not traditionally considered to be harmonious. I actually find some real beauty in this area. Look at We 3 & The Ho Chi Me as an example that plays with the tension created in secondary and tertiary colors.
Emotional Expression:I like to prioritize emotional expression over color theory, using color to convey a particular mood or feeling without necessarily following traditional rules. Like …a lot.
Personal Style: Artist better have a personal style. Sometimes mine intentionally disregards color theory. For example, I may prefer to use a limited color palette or focus on the texture and brushwork of the painting rather than adhering to traditional color combinations.
Conceptual Art: Artist’s should be more interested in exploring concepts and ideas through their work, rather than adhering to color theory. In this case, the artist may use color in a way that is subversive or unexpected, challenging the viewer's expectations and preconceptions. I do this quite a bit.

Ultimately, it's up to the you to decide whether to adhere to or disregard color theory in your work. As long as the artwork is aesthetically pleasing or thought-provoking to the artist and their audience, your choice is a valid one.