We used below swift functions for effects on image:

func getSepiaImage(image : UIImage , intensity : CGFloat) -> UIImage{
sepiaFilter = GPUImageSepiaFilter()
sepiaFilter.intensity = intensity

let outputImage = sepiaFilter.image(byFilteringImage: image)! as UIImage
return outputImage
}

//to get high contrast image filter
func getHighContrastImage(image : UIImage, intensity : CGFloat) -> UIImage{
contrastFilter = GPUImageContrastFilter()
contrastFilter.contrast = intensity

let outputImage = contrastFilter.image(byFilteringImage: image)! as UIImage
return outputImage
}

//to get high contrast image filter
func imageBlackAndWhite(image : UIImage) -> UIImage{
GrayFilter = GPUImageGrayscaleFilter()
let outputImage = GrayFilter.image(byFilteringImage: image)! as UIImage
return outputImage
}