One application that often comes up is measuring the color of clean liquids such as the fragrance sample seen above. This liquid fragrances is clear and looks almost like water. Fragrances such as this are often added to cleaning supplies, air fresheners, or other consumer products. One of the problems that this type of sample can experience is that the chemistry of the liquid fragrance solution can go bad and it will start to visually yellow. This is a concern of the manufacture because if the liquid fragrance yellows it cannot be added to the end product. Continue reading
important parameters. Hot peppers, used as relishes, pickled or ground into a fine powder for use as spices, derive their pungency from the compound capsaicin (8-methyl-N-vanillyl-6-enamide), a substance characterized by acrid and burning taste, that is located in the internal partitions of the fruit. First isolated in 1876, capsaicin stimulates gastric secretions and, if used in excess, causes inflammation. It is a tasteless, odorless white crystalline substance. Its level varies widely in capsicum peppers, from less than 0.05% in the mildly pungent types to as high as 1.3% in the hottest chilies. The pungency level is usually represented in Scoville heat values. Pungency levels vary in the same variety, by geographical region, and in maturity levels. Volatile oil content is low in all capscicums. The pigment responsible for the color in paprikas is capxanthin, a carotenoid. Other carotenoids present are capsorubin, zeaxanthin, lutein, kryptoxanthin and alpha and beta-carotene. Continue reading
These liquid visual color standards can be used as an independent test to verify instrumental Saybolt and ASTM D1500 Color measurement performance over time for these two visual color scales used to evaluate oil, oil additive and petrochemical color quality.
Bare metals are classified as opaque metals and do not allow any light to pass through them. In opaque metals, the specular reflection and diffuse reflection are key to defining the light interaction of this unique sample type. For bare metals both color and gloss are seen in the specular reflection which makes up a large portion of the reflection. Continue reading
HunterLab manufactures, directional 45/0 instruments and also diffuse sphere instruments, with diffuse/8˚ geometry. The UltraScan PRO, UltraScan VIS, ColorQuest XE, and ColorQuest XT are all bench top sphere instruments available from HunterLab. Continue reading
FAQ: ASTM D6290 recommends that I measure my plastic pellets for yellowness using the specular exclude mode. What is this?
FAQ: “More customers are asking us about Chinese Pharmacopeia Numbers… is this similar to EP/USP Color?
FAQ: “Do you sell a depolarizer for my HunterLab sphere instrument? On occasion we test polarized samples and there is definitely a dependence on the orientation of the lens. I was wondering if adding a depolarizer would eliminate this phenomenon?”
FAQ: “What is the limit on the standardization in TTRAN. Using the small sample flask, filled with Ultra pure water. If they follow the protocol, they expect to find values (CieLab: 100.0; 0.0; 0.0)?” Continue reading