Description

Colour measurement in the oils and fats industry is an essential part of the refining process. It is a means of assessing when the desired colour has been reached and when the refining can be halted.

This ability to regularly monitor the colour during processing cuts down the waste of refining materials and also helps to maintain colour consistency of the end product.

Scales & Values

Grading techniques are widely used to assess product colour by comparison with a representative series of fixed colour standards.

For many product types, a characteristic set of standards was agreed and adopted to aid colour control and the communication of coloour specifications; the result is a selection of traditional colour grading scales that have been adopted as industry standards and are still common today.

Your colour scale determines your instrument choice. We would be delighted to offer advice as to the correct colour scale and thus instrument choice for your application. Please do not hesitate to contact us.

Colour Scales:

  • AOCS-Tintometer® Colour
    • Colour scale used as a standard by the USA oil and fats refineries, rendering plants and companies trading or associated with the American edible oils and fats industry.
    • It is a modified red and yellow version of the Lovibond® RYBN Colour scale used for fats, oils and derivatives.
    • The AOCS-Tintometer® Colour Scale is a special red and yellow version of the Lovibond® RYBN scale using the AOCS-Tintometer Red Scale.
    • Please note: It uses the AOCS-Tintometer® Red scale, which is not the same as the Lovibond® standard Red scale.
    • Instruments that can be used: AF710-3; PFX880/AT – Heated; PFX 950 / 995/i/Heated; PFX/i-195/4 or PFX/i-195/7
  • beta Carotene (BS 684 Section 2.20)
    • beta Carotene is a strongly-coloured red-orange pigment abundant in plants and fruits. (e.g. beta Carotene is the substance in carrots that colours them orange.)
    • This scale is a direct measurement of beta carotene content of vegetable oils in ppm (part per million.)
    • Instruments that can be used: PFX 950 / 995 / i / Heated
  • Chlorophyll A & B (AOCS Cc 13d)
    • Chlorophyll is a green pigment found in almost all plants. It is vital for photosynthesis, which allows plants to obtain energy from light.
    • It is a poor absorber of green and near-green portions of the spectrum, hence the green color of chlorophyll-containing tissues.
    • This scales enables a direct measurement of chlorophyll A & B content of oils in ppm (parts per million.)
    • Instruments that can be used: PFX 950 / 995 / i / Heated
  • CIE L*a*b*
    • A Colour space in which values L*, a* and b* are plotted using a Cartesian coordinate system. Equal distances in the space approximately represent equal colour differences. L* represents lightness; a* represents the red/green axis; and b* represents the yellow/blue axis. CIE L*a*b* is a popular colour space for measuring both reflective and transmissive samples.
    • Instruments that can be used: most instruments in the Lovibond® range
  • Delta E* colour difference
    • Assessment of colour is more than a numeric expression. Usually it’s an assessment of the colour difference (delta) from a known standard. CIELAB (L*a*b*) and CIELAB (L*C*h) are used to compare the colours of two objects.
    • The expressions for these colour differences are DL*, Da*, Db*, or DL* DC* DH* (“D” symbolises “delta,” which indicates difference). Note: DH* is usually used instead of Dh to enable DE* to be calculated.
  • Dichromate Colour Index
  • FAC Colour (AOCS Cc13a-43)
    • Approved by the Fats Analysis Committee of the American Oil Chemists Society for grading dark coloured oils, fats and tallows. It includes 26 colour standards divided into 5 groups:
      • Scale 1 (1, 3, 5, 7, 9) for lighter coloured fats
      • Scale 2 (11, 11a, 11b, 11c) predominantly for yellow fats
      • Scale 3 (13, 15, 17, 19) for dark fats (red cast)
      • Scale 4 (21, 23, 25, 27, 29) for very dark fats, predominantly green
      • Scale 5 (31, 33, 35, 37, 39, 41, 43, 45) for very dark fats, predominantly red
      • Instruments that can be used: PFX 195/3 / 950 / 995 / i / Heated or FAC Comparator
  • Gardener Colour
    • The Gardner Colour scale as specified in ASTM D1544 is a single number, one dimensional, colour scale for grading the colour of similarly coloured liquids such as resins, varnishes, lacquers, drying oils, fatty acids, lecithin’s, sunflower oil and linseed oil
    • The scale ranges from a pale yellow to a red in shade and is described in terms of the values 1-18. The glass standards used with the comparator can achieve a resolution of 1 unit, automatic PFX and PFXi instruments 0.1
    • Instruments that can be used: AF334; Gardener Comparator; various instruments within the PFX range.
  • Kreis Value (Rancidity in Fats)
    • A colorimetric test that uses the colour produced by the action of chemical reagents as a quantitative assessment of oxidative rancidity of fats and oils
    • The results are reported to be reproducible to 5 – 10%. Using this test, deterioration due to oxidation may be detected at a very early stage; fresh fats and oils that have not been kept under oxygen-free conditions give a positive reaction
    • Instruments that can be used: PFX 995 / i / Heated
  • Lovibond® RYBN Colour
    • 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.
    • Instruments that can be used: PFX range
  • Optical density (Absorbance)
    • Please note; with both our PFX and PFXi ranges Absorbance is referred to as Optical Density (OD). This is an available Colour Scale.
    • Absorbance should not be confused with Absorptance (the fraction of light absorbed by a sample.)
    • Instruments that can be used: PFX range
  • Platinum-Cobalt / Hazen / APHA Colour (ASTM D 1209)
    • Often referred to as Pt-Co, Platinum-Cobalt, Hazen or APHA Colour. All terms are interchangeable and equally valid
    • Used to measure clear to dark amber liquids
    • Used extensively in the water industry but also for clear oils, chemicals and petrochemicals such as glycerine, plasticisers, solvents, carbon tetrachloride and petroleum spirits
    • Instruments that can be used:
      • AF329, 0 – 250 mg Pt/l, discs (CAA, 0 – 30 mg Pt/l; CAB, 30 – 70 mg Pt/l; NSB, 70 – 250 mg Pt/l
      • AF325, 10 – 250 mg Pt/l, discs (NSH, 10 – 90 mg Pt/l; NSB, 70 – 250 mg Pt/l)
      • AF328, Low Range, 0 – 70 mg Pt/l, discs (CAA, 0 – 30 mg Pt/l; CAB, 30 – 70 mg Pt/l)
      • AF327, Low Range, 0 – 70 mg Pt/l, discs (1209/1, 0 – 30 mg Pt/l; 1209/2, 30 – 70 mg Pt/l)
  • xyY chromacity co-ordinates
    • The coordinates x, y, and z are derived from the XYZ Tristimulus values by the following calculation such that x + y + z = 1, x = X/(X + Y + Z), y = Y/(X + Y + Z), z = Z/(X + Y + Z)
    • The values of x and y can then be used to pinpoint a colour in the x y coordinate system. The x and y chromaticity coordinates are generally reported along with the value of luminance factor Y
    • Instruments that can be used: most instruments in the Lovibond® colour range
  • XYZ tristimulus values
    • The CIE XYZ 1931 Tristimulus system is a modified version of the RGB colour tristimulus system and uses non real or imaginary stimuli. This innovation allows all colours within its gamut to be expressed as positive numbers, unlike the RGB system, where some colours fall outside its gamut and are expressed as negatives. The XYZ chromaticity co-ordinates are defined as x,y,and z
    • Instruments that can be used: most instruments in the Lovibond® colour range
 

Please send us an email explaining what you would like to test, your colour application and environment and we will send you a brochure with specifications based on your requirements.

Please send us an email explaining what you would like to test, your colour application and environment and we will recommend a suitable Lovibond® Tintometer colour testing instrument.

Additional information

Weight 0.00 kg