Lovibond comparator

Love My Carpet Lovibond Comparator Low alcohol beers Low alloy steel Low density lipoprotein... 

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... 

Liquid junction potential 63, 549 Literature of analytical chemistry 6, 122, 156, 251, 253, 498, 499, 640, 641, 813, 815 Lithium, D. of as aluminate, (g) 459 Litmus 265 Litre xxix, 78 Littrow mounting 661 Logarithms four figure, 843 Lovibond comparator 655 Low voltage d.c. arc 763, 771 Lubricants for glass stopcocks 85 Lyophilic colloids 419 Lyophobic colloids 419 stability of, 419... 

The preparation of reference standards in this procedure is a tedious task and may require considerable time. Time can be saved by applying what is called a permanent colour standard method, which requires a special device, the so-called comparator. The Lovibond comparator, shown on Fig. 1.8 employs nine permanent glass colour standards, fitted on a revolving disc. The device is fitted... 

A determination of the approximate pH of the solution is made with a universal or wide range indicator or with an indicator test paper (see under Section I.22.A) and then the suitable disc is selected and inserted into the comparator. A specified amount (with the Lovibond comparator 10 ml) of the unknown solution is placed in the glass test tube or cell, the appropriate quantity of indicator (normally 0-5 ml) is added and the colour is matched against the glass disc. Provision is made in the apparatus for the application of the Walpole technique by the insertion of a blank containing the solution. It is claimed that results accurate to 0-2 pH unit can be achieved. 

The topic of color standards is a subject broad enough for its own monograph. Traditional color standards date back centuries for comparison of paint pigments, the color and clarity of oil and beer (Lovibond comparators), precious gems, and a variety of other applications in which... 

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. 

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. 

Figure 6. Unsaturated galacturonides as nonenzymatic browning precursors. Hellige units are obtained by comparing color of sample with color of tinted glass discs according to the Lovibond principle. (Reproduced with permission from ref. 39. Copyright 1988 Springer.)...

---