ISO 12646:2015

Overview

ISO 12646:2015 - Graphic technology - Displays for colour proofing - Characteristics defines requirements and test methods for displays used in soft proofing of colour images. The standard specifies two conformance levels (Class A and Class B) and addresses key electro‑optical properties such as uniformity, viewing‑angle behaviour, calibration aims and stabilization. Its purpose is to help manufacturers, colour managers and prepress professionals ensure that a display can reliably represent proofs intended to match hard‑copy output.

Key topics and technical requirements

• Conformance levels: Two levels (Class A and Class B) are defined to address differing soft‑proofing needs (ISO 14861 compatibility is emphasized).
• Calibration aims: Default calibration for testing is a luminance of 160 cd/m², white point at D50 (x=0.3457, y=0.3585, 2° observer) and gamma ≈ 2.2. Test results must report any deviation from these aims.
• Stabilization (warm‑up): Displays must be operated in calibration mode for 12 hours in a controlled room (18–28 °C, ±0.5 °C). Stability is reached when luminance change < 2% (compared to the average of the last 9 hours) and white point within ±0.005 Δx, Δy.
• Uniformity testing: Tonality and colour uniformity use a 5×5 grid of measurements referenced to the centre patch. Colour differences are evaluated in CIELAB using ΔE00; for white and mid‑grey driving levels DE00 should be ≤ 4.
• Tonality uniformity metric: Luminance ratios for grey and white (e.g., RGB = 127 and 255 for 8‑bit) are used to compute deviations; the maximum deviation should be < 10%.
• Viewing cone / angle measurements: The standard prescribes geometry and measurement methods for viewing‑angle dependent variations (horizontal, vertical, diagonal and 45° positions) to quantify how electro‑optical properties change with viewing direction.
• Test methods & instrumentation: Includes photometric, colorimetric and spectroradiometric measurement conditions and preparation procedures.

Applications and who uses it

• Display manufacturers qualifying panels for the graphic arts market.
• Prepress and proofing labs that implement soft proofing workflows.
• Colour management engineers and quality assurance teams wanting reproducible proofs that match hard copy.
• OEMs and system integrators designing viewing cabinets or proofing stations compliant with ISO 14861.

Related standards

• ISO 14861 (soft proofing systems)
• ISO 13655 (spectral measurement / colorimetric computation)
• CIE Publication 122 and IEC 61223‑2‑5 (useful background on display evaluation)

ISO 12646 is essential for anyone specifying or testing colour proofing displays, ensuring consistent soft proofs and better colour match between screen and print.