[css-color-hdr] reference suround for PQ

svgeesus · svgeesus · commit ad5199e2424b · 2020-05-31T21:07:00.000-04:00
diff --git a/css-color-hdr/Overview.bs b/css-color-hdr/Overview.bs
@@ -126,6 +126,9 @@ Predefined colorspaces for HDR: {#predefined-HDR}
 
 	The Perceptual Quantizer (PQ) electro-optical transfer function is used
 	[[SMPTE-ST-2084]],[[!Rec.2100]].
+	PQ assumes a reference viewing condition
+	where the scren surround
+	is at 5  cd/m².
 
 	ITU Reference 2100 is used for HDR 4k and 8k television.
 
