Re: [Gimp-user] Despeckling photos
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. https://www.fromoldbooks.org/ with fabulous vintage art and fascinating texts to read. Click here to have the slave make breakfast. ___ gimp-user-list mailing list List address:gimp-user-list@gnome.org List membership: https://mail.gnome.org/mailman/listinfo/gimp-user-list List archives: https://mail.gnome.org/archives/gimp-user-list
Re: [Gimp-user] Despeckling photos
On 12/4/19 1:44 AM, Liam R E Quin wrote: On Wed, 2019-12-04 at 03:39 +0100, Gimp_Noob wrote: I have several photos which I'd like to try to clean up as best I can. First, scan at higher resolution than yu plan to use. At least double. SOmetimes i find that select by colour works well. (1) make sure you have both blacks andwhites in your image, e.g. with levels or curves. (2) select by colour on a white area. (3) grow selection e.g. 2 pixels )4_ shrink selectin by 2 pixels (6) feather by 1 pixel (requires greyscale or RGB iamge, not indexed) (7) fill with white (e.g. drag the swatch from the toolbox, or use control-. or control-,) (8) select none repeat steps 2 to 8 with black instead of white. Can you explain what steps 3 and 4 acconplish? It seems like they should cancel each other. Gary ___ gimp-user-list mailing list List address:gimp-user-list@gnome.org List membership: https://mail.gnome.org/mailman/listinfo/gimp-user-list List archives: https://mail.gnome.org/archives/gimp-user-list
Re: [Gimp-user] Despeckling photos
On Wed, 2019-12-04 at 03:39 +0100, Gimp_Noob wrote: > I have several photos which I'd like to try to clean up as best I > can. First, scan at higher resolution than yu plan to use. At least double. SOmetimes i find that select by colour works well. (1) make sure you have both blacks andwhites in your image, e.g. with levels or curves. (2) select by colour on a white area. (3) grow selection e.g. 2 pixels )4_ shrink selectin by 2 pixels (6) feather by 1 pixel (requires greyscale or RGB iamge, not indexed) (7) fill with white (e.g. drag the swatch from the toolbox, or use control-. or control-,) (8) select none repeat steps 2 to 8 with black instead of white. slave liam -- Liam Quin - web slave for https://www.fromoldbooks.org/ with fabulous vintage art and fascinating texts to read. Click here to have the slave beaten. ___ gimp-user-list mailing list List address:gimp-user-list@gnome.org List membership: https://mail.gnome.org/mailman/listinfo/gimp-user-list List archives: https://mail.gnome.org/archives/gimp-user-list
Re: [Gimp-user] Despeckling photos
There are a lot of options. What I have used most is Wavelet Decompose (see here for an explanation - https://pixls.us/articles/skin-retouching-with-wavelet-decompose/ ). I fix old family photos that are usually full of scratches, etc. This technique works, but note it takes a lot of time to work on each layer. Check out more of Pat David's guides and YouTube where there are folks who've posted videos for using GIMP. Best search terms are: enhance, retouch, restore, fix, restoration, etc. GuyS -- “Happiness is the meaning and the purpose of life, the whole aim and end of human existence.” ― Aristotle On Tue, Dec 3, 2019, 8:39 PM Gimp_Noob wrote: > I have several photos which I'd like to try to clean up as best I can. > They all > have similar problems. They look like a bad copy of a black and white > photo with > large amounts of speckling. > > I'm not sure which tools to use. Should I use some combination of blurs or > masks?. Is there a particular tool that might be useful. Should the > contrast be > adjusted? I'm just looking to make minimal improvements. I know that I do > not > have a lot to work with. Any suggestions would be appreciated. > > Attachments: > * > https://www.gimpusers.com/system/attachments/1309/original/despeckling.png > > -- > Gimp_Noob (via www.gimpusers.com/forums) > ___ > gimp-user-list mailing list > List address:gimp-user-list@gnome.org > List membership: https://mail.gnome.org/mailman/listinfo/gimp-user-list > List archives: https://mail.gnome.org/archives/gimp-user-list > ___ gimp-user-list mailing list List address:gimp-user-list@gnome.org List membership: https://mail.gnome.org/mailman/listinfo/gimp-user-list List archives: https://mail.gnome.org/archives/gimp-user-list
