Measurement Methodologies
The Lovibond Scale matches the visual hue of the oil transmitted through an optical glass cell (typically 1-inch or 5¼-inch depth) against calibrated red and yellow glass filters. The Gardner Scale uses a 1-to-18 standardized amber liquid reference series, predominantly used in industrial coatings, polyols, and resin manufacturing.
Bleaching & Color Refinement at Nagdev Products
Natural castor oil contains carotenoids and chlorophyll pigments. In our automated continuous bleaching towers, the crude oil is treated with activated bleaching earth and activated carbon under vacuum (30–50 mbar) at 90°C–105°C, selectively adsorbing coloring matter to produce ultra-pale First Special Grade and Pale Pressed Grade (PPG) oils.
Frequently Asked Questions
Which castor oil grade offers the lowest Gardner colour? +
Pale Pressed Grade (NDEVOLEO™ PPG) and First Special Grade (NDEVOLEO™ FSG) offer the lowest color, achieving Gardner readings below 2.0 and Lovibond Red below 1.5.
Does darker color indicate chemical degradation in Commercial Castor Oil? +
Commercial grade is darker (amber to light brown) because it is expeller-pressed without bleaching earth. While chemically active for technical synthesis, it is not recommended for clear varnishes or skin care.