Color measurements Lovibond

Objective spectrophotometric color measurement, as described in AOCS Official Method Cc 13 50 (Firestone, 1998), gives results that are in general highly correlated with Lovibond color, although wide discrepancies occur with some oils (O Brien, 2003). Method Cc 13-50 is stated to be applicable to cottonseed, soybean and peanut oils, and requires revision to accommodate the use of double beam spectrophotometers. Its applicability to milk fat is not known. 

Color Measurement by Lovibond-Wesson (Cc 13b-45) determines the color of clear oil samples by comparison with glasses of known color characteristics. 

The color of the wax will affect the color of the finished product. A Lovibond Tintometer is often used for color measurements, whereby the color of the raw material is compared against a series of colored standard glasses, under a standard light source. The color of the solidified wax of the same sample may be different depending on the amount of occluded air, the rate of cooling, or surface finish. Therefore, the color of many waxes is best measured in the molten state. Two ASTM color standards are used to measure dark-brown to off-white color and off-white to pure white. The refractive index and the specific gravity are other parameters often determined. 

Lovibond [Tintometer]. TM for color measurement and water testing equipment used in standard methods specified by ASTM, AOCS, APHA, European and and U.S. Pharmacopoeia, ISO, BA, and IP. 

To some extent, the food technologist is today at a crossroads, and decisions which are made in the next few years will govern our whole approach to the problem of color measurement and color specification. Shall we, for example, specify color in terms of the C.I.E. quantities, or shall we proceed by measurement of color differences How do the Mun-sell, Lovibond, and other systems fit into such a plan ... 

The color of TSR L is measured with a Lovibond Comparator using methods outlined in the relevant International Standard (16). Raw mbber is molded into a disk 1.6 mm thick, and the color is compared and matched with that of standard glass disks. These glass disks provide a color index scale in which the higher index values correspond to darker colors. Generally the specification for TSR L is a maximum Lovibond individual value of 6 and range... 

Lovibond tintometer—device for measuring the color of a petroleum product, particularly petrolatums. The melted petrolatum is contained in a cell and the color is compared with a series of yellow and red Lovibond glasses. The length of the cell and the color standards that give the best match are reported. See color scale. 

Lovibond tintometer color can also be measured using objective automated instruments. In one version, the intensities of three light beams (red, yellow and white) transmitted by the oil are measured by photoelectric cells, and the results displayed as red and yellow color readings. The white light beam acts as a reference beam, and allows compensation for variation in the intensity of the light source (Rossell, 1986). AOCS Official Method Cc 13j 97 (Firestone, 1998) specifies how an automated tintometer should be used. However, this standard is valid only for refined oils. 

Refined and bleached (R B) color A measure of the amount of red color in the rendered fat is an indicator of the quality of both the starting material and the rendering techniques. This value is measured using the Lovibond 5.25-inch scale according to procedures described in AOCS Official Method Cc 13b 3 (39). The result is referred to as the AOCS Wesson color, the AOCS Lovibond color, or simply Lovibond color. The lower the value, the less colored the sample. 

The color of coconut is measured in a Lovibond Tintometer, using a 1-inch or 51 -inch cell for dark and hght colored oils, respectively. Results are given in red and yellow units describing the combination that matches the sample color. Alternatively, the optical density of the oil can be measured with the use of a spectrophotometer in a suitable cell at a wavelength of maximum absorbance. 

The Wesson method, which is the principal color method for the U.S. edible oil industry, has been used for many years primarily because of its simplicity. AOCS Method Cc 13b-45 (103) determines the color of a melted fat or oil product by comparison with red and yellow Lovibond glasses of known characteristics. This method, originally developed in England for measuring the color of beer, is only intended to assess the degree of redness. Yellow is necessary for assessment of redness by allowing the colors to closely match with that of oil sample the amount of yellow was considered unimportant for this method, and a fixed yellow ratio of... 

Sohd fat index, melting points, penetration, and viscosity are normally used to measure factors affecting consistency and texture (5, 35, 112, 113). Color is most frequently measured by the Lovibond procedure (5). 

The bleaching process is used to remove color bodies and other minor impurities. The bleaching adsorbent, usually a clay product, removes residual soap from alkali refining, aldehydes and ketones from decomposed peroxides, and color bodies. The color of bleached oil is widely measured by the Lovibond tintometer color scale. 

The Lovibond tintometer (IP 17) is used to measures the tint and depth of color by comparison with a series of red, yellow, and blue standard glasses. Waxes and petrolatum are tested in the molten state, and a wide range of cell sizes is available for the different types. 

The color of the oil becomes darker during frying. The change in color can be measured with a Lovibond tintometer. For a qnick assessment of color, comparison kits are available. As in the case of FFA, color alone does not express the quality of the used oil. 

Method Cc 13c-50, a photometric method, is designed to obviate some of the difficulties mentioned under use of the Lovibond. The measurements are made at selected wave lengths, for which empirical constants are developed to correlate the reading with the Lovibond. This reading, the so-called photometric color D, a modified optical density, is defined thus ... 

The physical constants of citrus seed oil reported by Braddock and Kesterson (1973) are given in Table 7.2. Refined oil is bland and pale yellow in color and could be used like other cooking and salad oils. Helmy (1990) studied the effect of refining on color and reported that refined oil from orange, bitter orange, mandarin and lemon ranged from 9 to 13 lovibond units (yellow) and bleached oils measured 1 lovi-bond unit. The oil has been evaluated for edible purposes as well as industrial applications (Hendrickson and Kesterson, 1961, 1963, 1964, 1965 Kaplan, 1941 Stambovsky, 1942). 

The bloom or cast of lubricating oils observed in reflected light can be measured by the Bloom Index. It. measures how much the blue or the yellow predominates in reflected Lovibond colors. 

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