[css-color-4] Lab/LCH/Oklab/Oklch clarifications

Author: svgeesus

css-color-4/Overview.bs

@@ -2819,16 +2819,14 @@ Device-independent Colors: CIE Lab and LCH, Oklab and Oklch</h2>
 	<!-- But now we have Oklab so where it matters, be more specific -->
 
 	<dfn value export for="lab()">Lab</dfn> is a rectangular coordinate system
-	with a central Lightness axis.
+	with a central Lightness (L) axis.
 	This value is usually written as a unitless number;
-	for compatibility with the rest of CSS, it is written as a percentage.
+	for compatibility with the rest of CSS, it may also be written as a percentage.
 	100% means an L value of 100, not 1.0.
-	L=0% is deep black (no light at all)
-	while L=100% is a diffuse white
+	L=0% or 0 is deep black (no light at all)
+	while L=100% or 100 is a diffuse white.
 
-	Values of L greater than 100 would correspond to specular highlights,
-	but their precise color is undefined in this specification.
-	Usefully, L=50% is mid gray, by design,
+	Usefully, L=50% or 50 is mid gray, by design,
 	and equal increments in L are evenly spaced visually:
 	the Lab color space is intended to be <em>perceptually uniform</em>.
 
@@ -2889,7 +2887,7 @@ Device-independent Colors: CIE Lab and LCH, Oklab and Oklch</h2>
 	<!-- because Luv is not widely used nowadays, no need to say LCH(ab)
 	to distinguish from LCH(uv) -->
 
-	<p class="note">Note: The Lightness axis in Lab and LCH
+	<p class="note">Note: The L axis in Lab and LCH
 	is not to be confused with the L axis in HSL.
 	For example, in HSL, the sRGB colors blue (#00F) and yellow (#FF0)
 	have the same value of L (50%) even though visually, blue is much darker.
@@ -2963,11 +2961,11 @@ Device-independent Colors: CIE Lab and LCH, Oklab and Oklch</h2>
 	and chroma uniformity
 	compared to CIE LCH.
 
-	Like CIE Lab, there is a central lightness axis
+	Like CIE Lab, there is a central lightness L axis
 	which is usually written as a unitless number in the range [0,1];
 	for compatibility with the rest of CSS,
-	it is written as a percentage. 100% means an L value of 1.0.
-	L=0% is deep black (no light at all) while L=100% is a diffuse white.
+	it may be written as a percentage. 100% means an L value of 1.0.
+	L=0% or 0.0 is deep black (no light at all) while L=100% or 1.0 is a diffuse white.
 
 	Note: Unlike CIE Lab, which assumes adaptation to the diffuse white,
 	Oklab assumes adaptation to the color being defined,
@@ -3008,7 +3006,7 @@ Device-independent Colors: CIE Lab and LCH, Oklab and Oklch</h2>
 		</figcaption>
 	</figure>
 
-	Because Oklab is more perceptually uniform,
+	Because Oklab is more perceptually uniform than CIE Lab,
 	the color difference is a straightforward distance in 3D space
 	(root sum of squares).
 	Although trivial,
@@ -3073,7 +3071,7 @@ Specifying Lab and LCH: the ''lab()'' and ''lch()'' functional notations</h3>
 		parsing/color-valid-lab.html
 	</wpt>
 
-	The first argument specifies the CIE Lightness.
+	The first argument specifies the CIE Lightness, L.
 	This is a number between ''0%'' or 0
 	(representing black)
 	and ''100%'' or 100
@@ -3145,18 +3143,18 @@ Specifying Lab and LCH: the ''lab()'' and ''lch()'' functional notations</h3>
 		parsing/color-valid.html
 	</wpt>
 
-	The first argument specifies the CIE Lightness,
+	The first argument specifies the CIE Lightness L,
 	interpreted identically to the Lightness argument of ''lab()''.
 
-	The second argument is the chroma
+	The second argument is the chroma C,
 	(roughly representing the "amount of color").
 	Its minimum useful value is ''0'',
 	while its maximum is theoretically unbounded
 	(but in practice does not exceed ''230'').
 	If the provided value is negative,
 	it is clamped to ''0'' at parsed-value time.
 
-	The third argument is the hue angle.
+	The third argument is the hue angle H.
 	It's interpreted similarly to the <<hue>> argument of ''hsl()'',
 	but doesn't map hues to angles in the same way
 	because they are evenly spaced perceptually.
@@ -3307,17 +3305,17 @@ Specifying Lab and LCH: the ''lab()'' and ''lch()'' functional notations</h3>
 			parsing/color-valid.html
 		</wpt>
 
-		The first argument specifies the Oklch Lightness,
+		The first argument specifies the Oklch Lightness L,
 		interpreted identically to the Lightness argument of ''oklab()''.
 
-		The second argument is the chroma.
+		The second argument is the chroma C.
 		Its minimum useful value is ''0'',
 		while its maximum is theoretically unbounded
 		(but in practice does not exceed ''0.5'').
 		If the provided value is negative,
 		it is clamped to ''0'' at parsed-value time.
 
-		The third argument is the hue angle.
+		The third argument is the hue angle H.
 		It's interpreted similarly to the <<hue>> arguments
 			of ''hsl()'' and ''lch()'',
 		but doesn't map hues to angles in the same way.