diff --git a/color/color-common.ts b/color/color-common.ts
index ec663a863..0de2a470c 100644
--- a/color/color-common.ts
+++ b/color/color-common.ts
@@ -115,7 +115,7 @@ export class Color implements definition.Color {
     }
 
     private _parseComponents() {
-        if (!this._argb) {
+        if (types.isUndefined(this._argb)) {
             throw new Error("Missing the ARGB numeric value");
         }
 
diff --git a/color/known-colors.ts b/color/known-colors.ts
index ab04e9c9e..32dbc8846 100644
--- a/color/known-colors.ts
+++ b/color/known-colors.ts
@@ -1,4 +1,5 @@
-export var AliceBlue = "#F0F8FF";
+export var Transparent = "#00000000";
+export var AliceBlue = "#F0F8FF";
 export var AntiqueWhite = "#FAEBD7";
 export var Aqua = "#00FFFF";
 export var Aquamarine = "#7FFFD4";