Stark, EmilyTurton, Terece LBujack, RoxanaEl-Assady, MennatallahOttley, AlvittaTominski, Christian2025-05-262025-05-262025978-3-03868-282-0https://doi.org/10.2312/evs.20251081https://diglib.eg.org/handle/10.2312/evs20251081Recent work has proven the non-Riemannian nature of perceptual color space by identifying the existence of diminishing returns along the luminance axis. A lurking question is if the luminance channel might somehow be the only axis that exhibits diminishing returns. In this short paper, we report on a companion study along two color axes: green to pink and blue to orange. These paths through color space were chosen as the most likely ones to form geodesics based on maximal agreement between color similarity experiments and hue constancy experiments. Our crowdsourced studies confirmed the existence of diminishing returns along both lines of color studied, bolstering the evidence that perceptual color space is non-Riemannian.Attribution 4.0 International LicenseCCS Concepts: Human-centered computing → Empirical studies in visualization; Visualization theory, concepts and paradigmsHuman centered computing → Empirical studies in visualizationVisualization theoryconcepts and paradigms10.2312/evs.202510815 pages