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  "framework" : "CoreImage",
  "identifier" : "/documentation/CoreImage/CIFilter-swift.class/saturationBlendMode()",
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  "title" : "saturationBlendMode()"
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# saturationBlendMode()

Blends the colors and saturation values of two images.

```
class func saturationBlendMode() -> any CIFilter & CICompositeOperation
```

## Return Value

The modified image.

## Discussion

This method applies the saturation-blend mode filter to an image. The effect uses the values of the hue and luminance from the background image with the saturation of the input image to produce the output.

The saturation-blend mode filter uses the following properties:

- `inputImage`: An image with the type [`CIImage`](/documentation/CoreImage/CIImage).
- `backgroundImage`: An image with the type [`CIImage`](/documentation/CoreImage/CIImage).

The following code creates a filter that results in the image taking on the colors of the background image with low saturated values becoming gray.

```swift
func saturationBlendMode(inputImage: CIImage, backgroundImage: CIImage) -> CIImage {
    let colorBlendFilter = CIFilter.saturationBlendMode()
    colorBlendFilter.inputImage = inputImage
    colorBlendFilter.backgroundImage = backgroundImage
    return colorBlendFilter.outputImage!
}
```

![The image on the top left shows a beach with multiple palm trees and a rainbow arching across the blue sky.  The image below is a gradient image displaying a gradual color shift from purple to a dark orange. The image on the right shows the output from applying a saturation-blend mode filter. The result displays a gray beach with not much visible detail and only the colors from the gradient photo visible.](images/com.apple.coreimage/media-3546404@2x.png)

---

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