Comparative Analysis of Low-Cost Portable Spectrophotometers for Colorimetric Accuracy on the RAL Design System Plus...

Area of Science:

• Color Science
• Metrology
• Instrumentation

Background:

• Traditional spectrophotometers and calibrated RGB cameras are used for colorimetric measurements.
• Novel low-cost portable spectrophotometers present a potentially more accessible alternative.
• Evaluating the colorimetric accuracy of these new devices is crucial for their adoption.

Purpose of the Study:

• To assess the colorimetric accuracy of low-cost, portable spectrophotometers.
• To compare their performance against established color calibration targets and RGB cameras.
• To determine their suitability as alternatives in scientific and industrial settings.

Main Methods:

• Tested four low-cost spectrophotometers (Nix Spectro 2, Spectro 1 Pro, ColorReader, Pico) and a smartphone RGB camera.
• Utilized the RAL Design System Plus (RAL+) color calibration target with 183 colors.
• Measured color differences in the CIELAB color space using the CIEDE2000 (ΔE) metric.

Main Results:

• Nix Spectro 2 demonstrated the highest performance, matching 99% of RAL+ colors with ΔE values of 0.5-1.05.
• Spectro 1 Pro and ColorReader matched approximately 85% of colors (ΔE: 1.07-1.39).
• Pico and the smartphone camera showed lower accuracy, matching 54-77% of colors (ΔE: ~1.85).

Conclusions:

• Low-cost portable spectrophotometers provide excellent colorimetric measurement capabilities.
• These devices generally outperform RGB camera-based systems in color accuracy.
• They represent valuable, cost-effective tools for color analysis in science and industry.