diff --git a/src/PenSkin.js b/src/PenSkin.js
index ba94d23..89b09bc 100644
--- a/src/PenSkin.js
+++ b/src/PenSkin.js
@@ -181,7 +181,7 @@ class PenSkin extends Skin {
         const r = Math.round(color4f[0] * 255);
         const g = Math.round(color4f[1] * 255);
         const b = Math.round(color4f[2] * 255);
-        const a = Math.round(color4f[3]);   // Alpha is 0 to 1 (not 0 to 255 like r,g,b)
+        const a = color4f[3];   // Alpha is 0 to 1 (not 0 to 255 like r,g,b)
 
         context.strokeStyle = `rgba(${r},${g},${b},${a})`;
         context.lineCap = 'round';