Batch GIMP script for auto-sharpen, white-balance and colour enhance

Like you, my point-and-shoot camera in auto-ISO mode often, if not always, gives me pictures which need a little adjustment to realise their full potential.

In GIMP, I usually use the 'auto white balance' option which usually gives great results. Often, I also use the 'auto color enhance' option and, occasionally, I use a simple filter to sharpen the features in the image.

Here's a GIMP script which will automate the process for a folder of pictures

	(define (batch-auto-fix pattern
	radius
	amount
	threshold)
	(let* ((filelist (cadr (file-glob pattern 1))))
	(while (not (null? filelist))
	(let* ((filename (car filelist))
	(image (car (gimp-file-load RUN-NONINTERACTIVE
	filename filename)))
	(drawable (car (gimp-image-get-active-layer image))))
	(plug-in-unsharp-mask RUN-NONINTERACTIVE
	image drawable radius amount threshold)
	(gimp-levels-stretch drawable)
	(plug-in-color-enhance RUN-NONINTERACTIVE
	image drawable)
	(gimp-file-save RUN-NONINTERACTIVE
	image drawable filename filename)
	(gimp-image-delete image))
	(set! filelist (cdr filelist)))))

view raw fix hosted with ❤ by GitHub

There are four input parameters. The first is the 'pattern' to find the files, e.g. "*.tiff" gives you all the tiff files in the directory. The next three inputs refer only to the sharpening filter. I use the (confusingly named) 'unsharp' filter which works by comparing using the difference of the image and a gaussian-blurred version of the image.

'radius' (pixels) of the blur (>1, suggested 5)
'amount' refers to the strength of the effect (suggested 0.5)
'threshold' refers to the pixel value beyond which the effects are applied (0 - 255, suggested 0)

These require a little bit of trial and error, depending on the type of picture. In the command line, the script is called like this:

 gimp -i -b '(batch-auto-fix "*.JPG" 5.0 0.5 0)' -b '(gimp-quit 0)'  

An obligatory example. Before:




and after:






Enjoy!