Hello all, could you take a look here: http://en.wikipedia.org/wiki/File:Justu ... ,_1636.jpg

and tell me how to clean the white dots/blocky/patches thingy? I don't know how to do it with my arsenal of GIMP knowledge. The picture is big, 2500x3176.

Thank you

I'd see two methods:

- Lazy easy: go for a gentle overall blur then erase the blur you don't want for critical details.
Pros: fast, Cons: difficult to maintain a unified grain.

- No rush: try to select what makes the dots clashing with the rest, try color selection maybe then erase what you don't want in this selection, then play with curves or brightness/contrast to finetune those cracks and dots to your need.
Pros: possibly more grain accurate, Cons: trial and error is longer.

You can get carried away with technicalities and overlook the obvious.

The first thing I thought was 'fast-fourier-transform' (maxed out the cpu with this one, lol) or maybe a 'wavelet-denoise'
but a simple filters -> generic -> erode works just as well with this image. The face and the hands do suffer, so work on a duplicated layer then add a layer mask and restore those areas.

screenshot with inset for a comparison.

I got an acceptable result with:
1 - duplicate layer
2 - apply Filters/GMIC > Enhancements > Smooth (mean-curvature)
3 - apply Filters/Enhance/Despeckle
4 - changing the layer mode to "Darken only"
5 - file > export or override
You can try various amounts on the filter (checking on the preview), I used high values

oh cool let try ...

The problem i see is that the photo seems no too bad but the is the painting to have suffered for the passing time ... it may be enhanced digitally anyway this may be no truthful to the original

And also i will not start trying if i had to be too faithful to the original...

the idea is to edit at original size , correct ?

i am exploring a idea , for sure i had some adapt plugin (i think " wavelet denoise " , followed by a very delicate use of gimp anistropic smoothing would do most of the trick ) that should do even better


...but i want try manually something different ...

Done a detail to show the effect at original size



the last of the 2 is at original size ( i uploaded by mistake ) this just below was instead scaled for gc









what i did :

to get rid out of the white noise on dark area

Even before start edit duplicate the layer and work with the dup

1) selecte the face ,hands and the few other whitish area
(first using color selector, then polishing in quickmask)
2 feathered and inverted the selection
3) a generous amount of gaussian blur , on original size were 16 in the darkest area were no details that could get lost by blur ...also because next step very important
4) EDIT/FADE , change mode from default "replace" to "darken only" ...so the effect of 3, the blur will mostly work on white noise but with almost no side effect on dark area ( the highlight to protect were already deselected),...you may lower opacity a bit so the noise instead that be totally merged remain as a hint of a vague texture

5) invert selection , start gmic , change "output option " to "new layer"
I used Graphic Novel, , setting used are embedded in the layer name ,in the xcf i am going to post :
6) again as for 5 but for the inverted selection, this new layer was used with low opacity
7) new layer from visible and blur of 1px
8 ) duplicate of the layer apply unsharpmask2



blur again this time of 4 and change layer mode to "Darken only " this is to softly enhance contrast of dark details in the hands face and lightest area

not sure where upload at original size the xcf or even the png...humm maybe on my DA


PS then to make more similar to the original would be possible add some grain
Except that original painting should have no any "grain" but brush strokes that were no visible in the photo ...

No one technique work (i.e., don't ask; lol. OK; some hints. Anisotrophic smoothing, bilateral filter, and gausean blur (9pix) using edge detect to amplify the specs for a mask. Then additional manipulations such as selective smudging and clone/heal brush). Still had some fine cracks that shown, so hid most of that with using a Virtual Photographer preset which added glow to the piece (and dupped that layer separating light and dark with various opacities). Can use some more tlc, but I tire after spending more then 25 minutes. lol

I used Iain's Noise Reduction G'MIC filter as a first pass to remove low level noise. The spots and cracks remain. Then I created a new layer with a small radius median filter to remove the small cracks and spots on the dark areas using a mask. Then a another layer with a wider median filter, set to darken only, and more masking to remove the bigger cracks. And the last layer is duplicated, set to lighten only, and the mask edited so that the dark marks on the skin are removed. Finally I used the original image, with a mask to replace some of the areas that were obviously degraded.

Several techniques, different opinions that their method leads to a good result.
Just the result is the difference, but here is perhaps the ideal! I think we should preserve the most original, and just attack the imperfections.

But it is interesting to see what you get with images and different techniques. At least I learn a lot from this.

PhotoComix, why your Unsharp Mask is so different? Mine only has 3 settings: Radius, Amount and Threshold

lylejk, Nice result, that "Virtual Photographer preset" has in Gimp? Interessant!