Yarnell, AZ
Trader Joe's has, at $6 a bottle, a bordeaux wine called Le Haut-Mèdoc de Giscours, which is a light, snappy, red with softened astringincy and plenty of long lasting plum and cherry. In the glass it appears deep rose with blue overtones.
I mean a brightness of 69 and a .39 warmth.
Warmth and Brightness
Those are the descriptive names of the parameters I have finally distilled from all that data. Warmth is a measure of the orange-yellow-brownness of the color. A cool color has less yellow-orange. It appears to be purple-blue because yellow-orange and purple-blue are opposites on the color wheel. Wines I tested have warmth values ranging from 0.367 to 0.574.
Brightness indicates how much color you see. The more light that gets through the wine, the brighter it appears. Red wines I looked at have brightnesses between 61.2 and 98.8. Here are two wines, a 1998 Italian chianti on the left and a 2002 Australian shiraz on the right:
The chianti is a robustly warm wine, especially so for a wine that is barely 5 years old. It's Warmth is 0.54, nearly the highest of all the wines tested, versus 0.37 for the shiraz, which is described as blue-purple. The chianti is also noticibly lighter than the shiraz, their Brightnesses are 95 and 80 respectivly.
Here are the Brigtness and Warmth values for seven wines I tested, then I'll explain how the numbers are calculated:
All of the red wine spectra have the same basic shape: the foot is in the yellow-orange area from 600-645 nm. The shoulder is red light - it extends from 645-700 nm. Transmittance values at 600, 645 and 700 nm, have been previously tabulated as Ty, Tmid and Tr. Two intermediate parameters, R1 and R2 are calculated, R1 represents the area under the yellow-orange part of the spectrum, and R2 is the normalized area under the red part of the curve:
R1 = (Tmid - Ty)/2 + Ty
R2 = (Tr - Tmid)/2 + (Tmid - Ty)
Warmth is the ratio of the yellow-orange component to the normalizedred component:
Warmth = R1/R2
Brightness is the sum of the the yellow-orange component and the total red componentBrightness = R1 + R2 + Ty
Now I can describe the color of wine with two intuitive parameters, brightness and warmth that convey an observable perceptual reality. As a bonus, I can do the test with only three measurements and no dilution. Yeah!
