diff --git a/build.properties b/build.properties
index c49d721e..d3857deb 100644
--- a/build.properties
+++ b/build.properties
@@ -6,7 +6,7 @@
 PROJECT: openseadragon
 BUILD_MAJOR: 0
 BUILD_MINOR: 9
-BUILD_ID: 117
+BUILD_ID: 118
 BUILD: ${PROJECT}.${BUILD_MAJOR}.${BUILD_MINOR}.${BUILD_ID}
 VERSION: ${BUILD_MAJOR}.${BUILD_MINOR}.${BUILD_ID}
 
diff --git a/openseadragon.js b/openseadragon.js
index 934fa1df..0a843880 100644
--- a/openseadragon.js
+++ b/openseadragon.js
@@ -1,7 +1,7 @@
 /*globals OpenSeadragon*/
 
 /**
- * @version  OpenSeadragon 0.9.117
+ * @version  OpenSeadragon 0.9.118
  *
  * @fileOverview 
  * <h2>
@@ -9309,7 +9309,7 @@ function blendTile( drawer, tile, x, y, level, levelOpacity, currentTime ){
     }
 
     deltaTime   = currentTime - tile.blendStart;
-    opacity     = Math.min( 1, deltaTime / blendTimeMillis );
+    opacity     = Math.min( 1, deltaTime / ( blendTimeMillis || 1 ) );
     
     if ( drawer.alwaysBlend ) {
         opacity *= levelOpacity;
diff --git a/src/drawer.js b/src/drawer.js
index 4a76a056..25469463 100644
--- a/src/drawer.js
+++ b/src/drawer.js
@@ -784,7 +784,7 @@ function blendTile( drawer, tile, x, y, level, levelOpacity, currentTime ){
     }
 
     deltaTime   = currentTime - tile.blendStart;
-    opacity     = Math.min( 1, deltaTime / blendTimeMillis );
+    opacity     = Math.min( 1, deltaTime / ( blendTimeMillis || 1 ) );
     
     if ( drawer.alwaysBlend ) {
         opacity *= levelOpacity;