Re: [Gimp-user] Despeckling photos

[Liam R E Quin <liam holoweb net>]

On Fri, 2019-12-20 at 21:12 +0100, Gimp_Noob wrote:
> What should I do if I only have a .jpg file? In other words,there is
> nothing to scan. If I remove too many speckles it looks fake.

There's no simple answer - you have to d the best you can with what
you've got. Sometimes resizing (image->scale) by a factor of 3 can
help: open image->scale image, append
  * 3
to the width
and press tab, and GIMP will do the multiplication :) Use "cubic"
interpolation.

Then blur the now-larger image with radius 5. Then scale back down
(again cubic but you could use / 3 instead of * 3 to have GIMP do the
division) and then sharpen (filters->enhanve/>unsharp mask).

Technically what's going on is that this procedure will give the image
a wider number of pixel values - more greys - especially in 16 or 32
bit - and reduce some of the effects of jpeg artifacts.  <ale sire the
image is in greysvcale/grayscale or RGB mode first, not indexed, or it
won't help.

-- 
Liam Quin - web slave for https://www.fromoldbooks.org/
with fabulous vintage art and fascinating texts to read.
Click here to have the slave make breakfast.