ConclusionThis article proposes a dual-light source structure for spec-trophotometers that measure samples under both SCI and SCEconditions. Existing design uses a light trap in the integratingsphere, which compromises the sphere structure and the diffu-sion of illumination. This causes SCI measurement for sampleswith same color but different surface gloss to be less accurate.Furthermore, because different instruments’ light traps have dif-ferent size and design, they have low inter-instrument agreementunder SCE condition. This article proposes a structure that uses twolight sources in place of the light trap, and verifies the structurewith experiment results. The experiment results show that underboth SCI and SCE conditions, the dual-light source structure is sig-nificantly superior to the current design, and is more suitable forinstruments that measures under both SCI and SCE conditions. Thedual-light source structure has high practical value