diff --git a/src/steps/downloadStep.tsx b/src/steps/downloadStep.tsx
index 6d0163c773db3c07dfd482ca07f83006513d22f3..5e971d5a41f4ec26f2420e6fd0f4d482084a75a1 100644
--- a/src/steps/downloadStep.tsx
+++ b/src/steps/downloadStep.tsx
@@ -101,10 +101,10 @@ export class DownloadStep extends Step<DownloadStepState> {
         let raster = path.rasterize({ insert: false});
         raster.smoothing = "off";
 
-        var newCanvas = document.createElement('canvas');
-        const w = this.props.lab.data.pictureSize.width;
+        let newCanvas = document.createElement('canvas');
+        let w = this.props.lab.data.pictureSize.width;
         newCanvas.width = w;
-        const h = this.props.lab.data.pictureSize.height;
+        let h = this.props.lab.data.pictureSize.height;
         newCanvas.height = h;
 
         var newContext = newCanvas.getContext('2d');