Testing colour-difference formulas from <i>LMS</i> colour spaces inspired in CIELAB

The CIELAB was recommended in 1976 as an approximately uniform colour space and colour-difference formula ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:mi>Δ</mml:mi> <mml:msubsup> <mml:mrow> <mml:mi>E</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>ab</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>*</mml:mo> </mml:mrow> </mml:msubsup> </mml:mrow> </mml:math> ) based on CIE XYZ tristimulus values. In this paper, first CIELAB is improved by keeping its structure and optimizing its four parameters in XYZ , LMS and X F Y F Z F spaces, resulting in modifications named MLAB( XYZ ), MLAB( LMS ) and MLAB( X F Y F Z F ), respectively. Then, CIELAB and these three modifications are evaluated in XYZ , LMS and X F Y F Z F colour spaces, respectively. From the combined and corrected (COM-corrected) visual dataset employed after the development of CIEDE2000 ( Journal of the Optical Society of America A 25, 1828–1834, 2008), using the standardized residual sum of squares (CIE 217:2016), we found that CIELAB and its modifications perform similarly in XYZ and X F Y F Z F spaces and perform worse in LMS colour space. It was also found that the three modifications to CIELAB performed significantly better than the original CIELAB in predicting the COM-corrected dataset, but significantly worse than the CIEDE2000 colour-difference formula (ISO/CIE 11664-6:2022), CAM16-UCS ( Color Research and Application 42, 703–718, 2017) and simple uniform colour space ( Optics Express 32, 3100–3122, 2024) spaces. The MLAB( X F Y F Z F ) space can therefore be tested as an approximately uniform colour space and colour-difference formula, following research proposed by CIE Technical Committee 1-98 (CIE 254:2024).