Lovibond® RYBN Colour
(AOCS Cc 13e, AOCS Cc 13j,ISO 15305, MS 252: Part 16, IP17 Method A)
Range: 0 - 70 Red, 0-70 Yellow, 0 - 40 Blue, 0-3.9 Neutral
Path Length: 1 - 153 mm (1/16" - 6") [Upgrade includes 5¼"]
In the 1890's, Joseph Lovibond, the founder of The Tintometer Ltd, developed the original Lovibond® Scale, based on a calibrated series of red, yellow, blue and neutral glasses.
After more than a century, The Tintometer Ltd still manufactures and grades the glass filters used for visual colour measurement in terms of Lovibond® units. It is this unparalleled knowledge and experience that are embodied into the Lovibond® PFX & PFXi 880, 950 & 995's.
The scale quoted by others as the Lovibond® scale does not guarantee validated Lovibond® Colour readings and may not conform with any visual instrument for Lovibond® Colour.
In contrast, The Tintometer Ltd can provide validation reports of correlation between Lovibond® values obtained on its automatic instruments and Lovibond® visual instruments.
Furthermore, our instruments uniquely include long sample chambers that house cells of up to a 6" path length, enabling the instrument to obtain direct Lovibond® colour readings, without multiplying errors, with 5 ¼" cells.
The Lovibond® Scale is based on 84 calibrated glass colour standards of different densities of magenta (red), yellow, blue and neutral, graduating from desaturated to fully saturated. Sample colours are matched by a suitable combination of the three primary colours together with neutral filters, resulting in a set of Lovibond® RYBN units that define the colour.
Since several million combinations are available, it is possible to match the colour of almost any sample; it is particularly popular for measuring the colour of oils and fats, chemicals, pharmaceuticals and syrups.
If, for any reason, an operator alters the method of use or changes any convention, it is important that they should give details when recording results, otherwise confusion could ensue.
For example, observers employ neutral filters to dull a bright sample, but omit to report the fact. In other cases they endeavour to make the best possible match without stating neutral values although they were needed, or use different colours in combination only in a fixed ratio according to some arbitrary convention.
The Lovibond® Scale provides its own simple language of colour which can fully describe the appearance of any colour in the least possible number of words and figures to avoid language difficulties. For convenience of laboratory records, or in communicating readings between laboratories, many industries record their results on a three colour basis, quoting the Red, Yellow and Blue instrumental values.
Some industries find it more convenient to simplify these terms by using the six divisions of the spectrum.
Orange - combination of red and yellow.
Green - combination of yellow and blue.
Violet - combination of red and blue.
These six terms are used in combination with "bright" and "dull".
A sample is described as being bright when the nearest possible match appears dull in comparison. When this occurs, neutral values are introduced and recorded as sample brightness.
A sample is described as being dull when red, yellow and blue are required to make a match. The value of the colour which is least is expressed as dullness.