diff --git a/src/Drawable.js b/src/Drawable.js
index 30a432a..197cf8d 100644
--- a/src/Drawable.js
+++ b/src/Drawable.js
@@ -95,10 +95,10 @@ Drawable._effectConverter = {
         return Math.max(1, Math.min(x, 512));
     },
     brightness: function(x) {
-        return Math.max(-100, Math.min(x, 100));
+        return Math.max(-100, Math.min(x, 100)) / 100;
     },
     ghost: function(x) {
-        return Math.max(0, Math.min(x, 100));
+        return 1 - Math.max(0, Math.min(x, 100)) / 100;
     }
 };
 
@@ -312,6 +312,8 @@ Drawable.prototype._setSkinCore = function (source, costumeResolution) {
 
     var options = {
         auto: true,
+        mag: this._gl.NEAREST,
+        min: this._gl.LINEAR, // TODO: mipmaps
         src: source
     };
     var willCallCallback = typeof source == 'string';
diff --git a/src/index.js b/src/index.js
index 3775c9e..2352ffe 100644
--- a/src/index.js
+++ b/src/index.js
@@ -29,7 +29,7 @@ function RenderWebGL(
     // TODO: remove?
     twgl.setDefaults({crossOrigin: true});
 
-    this._gl = twgl.getWebGLContext(canvas);
+    this._gl = twgl.getWebGLContext(canvas, {alpha: false});
     this._drawables = [];
     this._projection = twgl.m4.identity();
 
@@ -105,8 +105,8 @@ RenderWebGL.prototype.draw = function () {
     gl.clear(gl.COLOR_BUFFER_BIT);
 
     gl.enable(gl.BLEND);
-    gl.blendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA);
-    
+    gl.blendFuncSeparate(gl.ONE, gl.ONE_MINUS_SRC_ALPHA, gl.ZERO, gl.ONE);
+
     var currentShader = null;
 
     var numDrawables = this._drawables.length;
diff --git a/src/shaders/sprite.frag b/src/shaders/sprite.frag
index 7ee1cb8..d8f4966 100644
--- a/src/shaders/sprite.frag
+++ b/src/shaders/sprite.frag
@@ -108,9 +108,9 @@ void main()
 
 	#ifdef ENABLE_pixelate
 	{
-	    // TODO: understand why this padding helps clean up "pixel" edges
-	    const vec2 pixelPadding = vec2(0.125, 0.125);
-	    vec2 pixelTexelSize = u_skinSize * u_scale / u_pixelate;
+		// TODO: understand why this padding helps clean up "pixel" edges
+		const vec2 pixelPadding = vec2(0.125, 0.125);
+		vec2 pixelTexelSize = u_skinSize * u_scale / u_pixelate;
 		texcoord0 = (floor(texcoord0 * pixelTexelSize + pixelPadding)) / pixelTexelSize;
 	}
 	#endif // ENABLE_pixelate
@@ -186,4 +186,7 @@ void main()
 	#ifdef ENABLE_ghost
 	gl_FragColor.a *= u_ghost;
 	#endif // ENABLE_ghost
+
+	// WebGL defaults to premultiplied alpha
+	gl_FragColor.rgb *= gl_FragColor.a;
 }