Tintometer, Lovibond

Colour.—This is measured, when necessary, with the Lovibond tintometer,8 in which the colour of a layer of solution of definite thickness is compared with that of a series of coloured glasses of definite tints and intensities, these being combined so that they give the same tone and the same intensity of colour as the solution. The colour is then expressed in arbitrary degrees of red, yellow and black. 

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. 

Apparatus Use a Lovibond tintometer or the equivalent and a set of color comparison glasses that conform to the AOCS-Wesson Tintometer Color Scale (available from the National Institute of Standards and Technology). A minimum set of glasses consists of... 

Anonymous, Color Lovibond Method Using Color Glasses Calibrated in Accordance with the Lovibond Tintometer Color Scale, AOCS Official Method Ccl3e-92, American Oil Chemists Society, Champaign, Illinois, 1997. 

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. 

Lovibond color (unitless) Determines red/yellow intensity (carotenoids) of oil using Lovibond Tintometer Cc 13e-92... 

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. 

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. 

One of the simplest tristimulus colorimeters is the Lovibond Tintometer. The apparatus consists essentially of a viewing tube and light reflected from a standard white surface. One half of the field is illuminated by the light reflected by, or transmitted through, the specimen under examination. The other half is illuminated directly by a beam of standard light. Into the path of the latter beam coloured glass filters of the subtractive primaries are inserted and moved by mechanical means. 

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 Lovibond tintometer provides a well-known method of estimating the color of a solution in terms of standard glasses. Yellow, red, and blue glasses calibrated in Lovibond units are supplied. Various combinations of the glasses are observed to find... 

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. 

Lovibond tintometer Optical comparison instrument manufactured by Tintometer Ltd., for use of Lovibond glasses. 

Schofield, R. K. 1939. The Lovibond Tintometer adapted by means of the Rotham-sted device to measure colours on the C.I.E. system. J. Sci. Instr. 16, 74. 

Mix 0 1 ml of the oil, measured from a 1-ml pipette (graduated in 1/100th of a ml), in a test-tube with 5 0 ml of a 2 per cent solution of freshly redistilled aniline in glacial acetic acid, added from a burette. Examine the reaction mixture in a 1 -cm cell of the Lovibond tintometer after an interval of ten minutes. 

Although the original method was developed using a Lovibond tintometer for colour measurement, a more precise instrumental method could be employed. The colour absorbs at a maximum at 525 m/ and a 1-cm layer of a 0-008 per cent furfural solution under the given conditions has. an extinction of 0-70. 

The liquid oil samples are placed in a Lovibond 5 %" cell and the color is determined at 30°C by achieving the best possible match with the standard color slides of red and yellow indices using a Lovibond tintometer. 

The method determines the color of oils by comparison with Lovibond glasses of known color characteristics. The color of coconut oil is expressed as the sum total of the yellow and red slides used to match the color of the oil in a cell of the specified size in the Lovibond tintometer (I.S.I. 1984b). 

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