doc that previewtex uses transparent black border color

Fixes #2770

(Internal change: 2311916)

diff --git a/docs/spec_usdpreviewsurface.rst b/docs/spec_usdpreviewsurface.rst
index e2415c47e009d7c00257e82db24466fe27adfbf0..56038a79976e51fe0aab42f1f056feab47e18e8e 100644 (file)
--- a/docs/spec_usdpreviewsurface.rst
+++ b/docs/spec_usdpreviewsurface.rst
@@ -389,9 +389,10 @@ UDIM's.
 
 * **wrapS - token - useMetadata** 
 
-  Wrap mode when reading this texture.Possible Values:
+  Wrap mode when reading this texture. Possible values:
 
-    * *black* : Reader returns black outside unit square
+    * *black* : Reader returns transparent black (0.0, 0.0, 0.0, 0.0) outside 
+      unit square. 
 
     * *clamp* : extend edge values outside unit square