Subtractieve

Subtractieve, commonly rendered as subtractive in English, is an adjective used for approaches that achieve results by removing material, energy, or wavelengths from a whole. The term appears in several disciplines, including color theory, manufacturing, and audio synthesis, to distinguish from additive methods that build up components.

In subtractive color mixing, pigments or dyes absorb (subtract) certain wavelengths of light and reflect others. The traditional primary pigments are cyan, magenta, and yellow; mixing them tends to produce darker hues, culminating in black when combined at sufficient density. In practical applications such as printing and color reproduction, the CMYK model adds black ink to improve depth and accuracy, reflecting the subtractive nature of how pigments filter light rather than emit it.

Subtractieve manufacturing refers to processes that remove material to form parts. Common techniques include milling, turning, drilling, grinding, laser cutting, and waterjet cutting. This approach is contrasted with additive manufacturing, where material is deposited layer by layer. Subtractive methods are valued for producing precise tolerances, smooth finishes, and the ability to work with a wide range of materials, including metals and hard polymers. They also generate waste in the form of chips and require tooling strategies and post-processing steps.

In audio, subtractive synthesis begins with a rich, harmonically complex waveform produced by oscillators, then uses filters and envelopes to subtract harmonics and shape the sound over time. This method emphasized dynamic timbre control and has been a cornerstone of many classic analog synthesizers, distinguishing itself from additive synthesis, which constructs sound by combining many simple components.

The concept of subtraction underpins the term, though its specific meaning varies by field.