Fix UIVisualEffectView extra light blur being gray on white background

As far as I know the additional tint is a built-in feature of the UIVisualEffectView class. If you examine the view hierarchy with Xcode, you can see that there are two default subviews in the visual effect view instance: UIVisualEffectBackdropView and UIVisualEffectSubview. (I assume that these are private classes.) If you inspect UIVisualEffectSubview you can see that it has a background color which causes the unwanted tint that you've noticed.

I am not sure if there's an officially supported way to remove it, but you can modify this background color by filtering to the name of the private subview:

if let vfxSubView = visualEffectView.subviews.first(where: {    String(describing: type(of: $0)) == "_UIVisualEffectSubview"}) {    vfxSubView.backgroundColor = UIColor.white.withAlphaComponent(0.7)}

(Swift 5 compatible)

The default tint is around 70% opacity, so the easiest is to use the target background color with 0.7 alpha component.

I've also noticed that this might reset to the default value if the visual effect contains a custom subview. If I add this same snippet to the viewDidLayoutSubviews function of the view's controller, then it will keep the custom background color even after the built-in subview is updated.

Here's an example with a dark blur effect style. The top part shows the default tint and the bottom version has a custom black background color with 70% opacity.

If you just want the blur and your blurred view is gonna be stationary, you could use the UIImageEffects class and change the tintColor to a "full" white:

- (UIImage *)applyExtraLightEffect{    UIColor *tintColor = [UIColor colorWithWhite:0.97 alpha:0.82];    return [self applyBlurWithRadius:20 tintColor:tintColor saturationDeltaFactor:1.8 maskImage:nil];}

As far as I know you can't change it in the UIVisualEffectView.

You can try :

var visualEffectView = UIVisualEffectView(effect: UIBlurEffect(style: .Light))    visualEffectView.frame = imageView.boundsimageView.addSubview(visualEffectView)