---
title: unpremultiplyingAlpha()
framework: coreimage
role: symbol
role_heading: Instance Method
path: coreimage/ciimage/unpremultiplyingalpha()
---

# unpremultiplyingAlpha()

Returns a new image created by dividing the image’s RGB values by its alpha values.

## Declaration

```swift
func unpremultiplyingAlpha() -> CIImage
```

## Return Value

Return Value An image object representing the result of the operation.

## Discussion

Discussion Premultiplied alpha speeds up the rendering of images, but some custom filter routines can be expressed more efficiently with non-premultiplied RGB values. Use this method if you need to apply such a filter to an image that has premultiplied alpha.

## See Also

### Creating an Image by Modifying an Existing Image

- [applyingFilter(_:parameters:)](coreimage/ciimage/applyingfilter(_:parameters:).md)
- [applyingFilter(_:)](coreimage/ciimage/applyingfilter(_:).md)
- [transformed(by:)](coreimage/ciimage/transformed(by:).md)
- [transformed(by:highQualityDownsample:)](coreimage/ciimage/transformed(by:highqualitydownsample:).md)
- [cropped(to:)](coreimage/ciimage/cropped(to:).md)
- [oriented(forExifOrientation:)](coreimage/ciimage/oriented(forexiforientation:).md)
- [clampedToExtent()](coreimage/ciimage/clampedtoextent().md)
- [clamped(to:)](coreimage/ciimage/clamped(to:).md)
- [composited(over:)](coreimage/ciimage/composited(over:).md)
- [convertingWorkingSpaceToLab()](coreimage/ciimage/convertingworkingspacetolab().md)
- [convertingLabToWorkingSpace()](coreimage/ciimage/convertinglabtoworkingspace().md)
- [matchedToWorkingSpace(from:)](coreimage/ciimage/matchedtoworkingspace(from:).md)
- [matchedFromWorkingSpace(to:)](coreimage/ciimage/matchedfromworkingspace(to:).md)
- [premultiplyingAlpha()](coreimage/ciimage/premultiplyingalpha().md)
- [settingAlphaOne(in:)](coreimage/ciimage/settingalphaone(in:).md)