तपनीयमुज्ज्वाल्य रागत्रिभागं दद्यात्पीतरागं भवति ॥ कZ_०२.१३.५३ ॥
tapanīyam ujjvālya rāgatribhāgaṃ dadyāt pītarāgaṃ bhavati
After firing refined gold (tapanīya), one should add three parts of the colouring mixture (rāga); it becomes yellow-lustred (pītarāga).
It constrains discretionary variation by artisans, making output predictable and enabling audits of material consumption.