P _ _ _ _ _ _ for plastic is organic compounds added to a polymer base to give a specific color to plastics.

The term you are looking for is "pigments."

Pigments are organic compounds or inorganic compounds that are used to impart color to plastics and other materials. In the context of plastics, pigments are usually added to the polymer base during the manufacturing process to achieve a desired color, stability, and other properties.

Pigments can be categorized into various types, including:

1. Organic Pigments: These pigments are carbon-based and provide a wide range of colors. They tend to be brighter and more vibrant but may also be less stable under UV light and heat compared to inorganic pigments.

2. Inorganic Pigments: These are typically made from minerals and can provide excellent stability and opacity. Common examples include titanium dioxide, which is used for white coloring, and iron oxides, which are used for earth tones.

3. Special Effects Pigments: These include metallic or pearlescent pigments that can give a plastic a unique appearance.

The choice of pigment impacts the final appearance, durability, and processing characteristics of the plastic product. Therefore, manufacturers must carefully select appropriate pigments based on the intended application, cost, and performance requirements.