B1)  Parameters of Color Compared to Sound

The design of the chromaccord assumes fundamental parallels between sound and light.

                        SOUND                     LIGHT
                 A)    Pitch............................Hue
                 B)    Loudness...................Intensity
                 C)    Harmonics.................Perceptual contrast

                                                          (simultaneous and sequential contrast)

Other parameters:

Time parameters, such as duration and envelope, develop while performing in the medium.

Spatial motion and shape-change are important visual parameters, but creating and controlling motion is complex, violating the need for simple controls, especially if color variability is to be preserved. A digital chromaccord could incorporate motion and shape-change, but live control of both color and motion would remain complex. The absence of motion is a serious deficiency of the chromaccord as an instrument for vusic.

Sound timbre could be made parallel to visual texture.

Discussion:

A)   Pitch and hue are obvious parallels, but the wavelength of a hue cannot correspond to the wavelength of a pitch. The physics of color is so far removed from the physics of sound that there is no basis for any such scheme. Historically, many pitch-to-hue correspondence schemes have been put forth, but they all result from intuition or synaesthesia, e.g. Scriabin's Prometheus. The kinetic use of hue must be developed entirely in the context of visual experience.

B)    Loudness and intensity represent the abundance of sound and color respectively.

C)    Harmony and perceptual is a parallel that calls for further discussion.

Harmonic interactions between sounds lie at the heart of musical structures, both vertical and melodic, however visible light waves comprise less than one octave (wavelengths range from 400 nm to 700 nm), and wave interference can only be observed under specific conditions. Although "harmony" between colors is an aesthetic notion, the visual effects that occur between colors do depend on perceptual contrast.

When a color is exposed to an area of the retina, the color is perceived, and simultaneously a perceptual inhibition mechanism is initiated. Perceptual inhibition protects vision from excessive stimulus, but it also creates emphasis of any changes in the field of vision, a valuable survival mechanism. Inhibition of the stimulated receptors causes an imbalance in color perception that favors the color receptors that are not stimulated. When the stimulant is removed, the imbalance results in an illusory perception of the anti-hue of the stimulant, or the complementary color, an effect called "afterimage". The afterimage combines with any new color presented to that area of the retina, shifting the perception of the new color toward the compliment of the initial stimulant, causing the new color to appear to be more different from the original color than it actually is. This is sequential contrast.

The inhibition of stimulated receptor cells in the retina spreads through lateral tendrils of the neurons. You may have noticed that afterimages are fuzzy. At the edge between two color areas this lateral spreading of the complementarity in the receptors combines with the adjacent color causing the edge to appear to have greater contrast. This is simultaneous contrast.

As a chromaccord performance progresses, the performer needs to maintain a sense of continuity. Syntax for color change in useful.

B2) Chromatic Syntax

Chromaccord Index