Indian Standard Colour (ISC) Codes

Colour Ranges and Identification

• Grey is assigned to the range of 600-699.
• Violet is designated for the range of 700-799.
• Yellow, Cream, and Buff as well as Brown and Pink fall within the ranges of 300-399 and 500-599, respectively.
• New colours will receive unique numbers that do not overlap with existing figures.

Munsell System and Standards

• Munsell references aid in identifying colours based on hue, value, and chroma.
• The Indian Standard Colour (ISC) number is crucial for identifying specific colours.
• Colourimetric values, including chromaticity coordinates and luminance factors, are essential for standard colours derived from spectrophotometric measurements.

Key Colour Concepts

• Achromatic Attribute: Visual sensations devoid of hue.
• Additive Mixture: Combining light stimuli to produce visual sensations.
• Chromatic Colour: Colours distinguished from achromatic colours by their hues.
• Complementary Colours: Pairs of colours that can produce a specified achromatic colour when mixed.
• Dichroism: Changes in hue due to varying observing conditions (e.g., light source, concentration of materials).

Colour Measurement Definitions

• Tristimulus Value: Represents the amounts of primary colours needed to match a colour stimulus.
• Luminance Value: Measure of the brightness emitted by a surface, relative to ideal diffusers.
• Chromatic Coordinates: Determined by reflectance measurements over a defined wavelength range.

Munsell Colour Reference Example

• A complete Munsell reference such as "7.5 R, 9/2" indicates:
  • Hue: 7.5 R (red with a yellow-red inclination).
  • Value: 9 (very light colour).
  • Chroma: 2 (low colour strength).

Colour Range Values

• Neutral greys are identified with a prefix ‘N’ (e.g., N6, N8) indicating absence of hue or chroma.
• Munsell references allow for precise categorization of various colour types during design processes.