GIFSQ Tools · Module 08 — Meat, Poultry, Fish & Seafood · Tool 142 of 500
Analyse a meat colour reading: enter the CIE L*a*b* values from a colourimeter to get chroma, hue angle and a lightness verdict.
Try sample values — fills the form with the worked example below.
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Chroma C*
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Hue angle (degrees)
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Lightness L*
Equation: Chroma C* = square root of (a* squared + b* squared). Hue angle = arctangent of (b* ÷ a*), expressed in degrees from 0 to 360; when chroma is 0 the hue angle is 0 because the colour has no direction.
Method: CIE L*a*b* colour measurement for meat, ISO 11664-4 and CIE 15, following the AMSA Meat Color Measurement Guidelines. L* is lightness (0 black to 100 white), a* is redness (positive) to greenness (negative) and b* is yellowness (positive) to blueness (negative); chroma is colour saturation and hue angle is the colour direction, with 0 degrees red and 90 degrees yellow.
Assumptions: the colourimeter was calibrated with its white tile and the reading was taken on a freshly cut surface after blooming; the illuminant and observer are the same for every reading compared.
Limitations: L*a*b* describes the colour as the instrument sees it, not how a buyer will judge the meat in the shop; bloom time, fat cover and surface moisture all shift the values; hue and chroma are only comparable under the same illuminant.
Rounding: chroma and hue angle to 2 decimal places; lightness as entered; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Method: CIE L*a*b* colour measurement for meat, ISO 11664-4 and CIE 15, following the AMSA Meat Color Measurement Guidelines. L* is lightness (0 black to 100 white), a* is redness (positive) to greenness (negative) and b* is yellowness (positive) to blueness (negative); chroma is colour saturation and hue angle is the colour direction, with 0 degrees red and 90 degrees yellow.
Assumptions: the colourimeter was calibrated with its white tile and the reading was taken on a freshly cut surface after blooming; the illuminant and observer are the same for every reading compared.
Limitations: L*a*b* describes the colour as the instrument sees it, not how a buyer will judge the meat in the shop; bloom time, fat cover and surface moisture all shift the values; hue and chroma are only comparable under the same illuminant.
Rounding: chroma and hue angle to 2 decimal places; lightness as entered; intermediates unrounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: L* 45, a* 18, b* 10. Chroma = square root of (18 squared + 10 squared) = square root of 424 = 20.59; hue angle = arctangent of (10 ÷ 18) = 29.05 degrees — a red colour with some yellow.
Enter values above to see results.
Fresh beef is typically L* 35–45, a* 15–25, hue angle 25–40 degrees. Higher L* means paler meat. Tool 142 of 500 — GIFSQ
