Increase image size

[rimutaka]

Hi,

How to increase image size e.g. from 780x1040 to 1920x1080 pxl without reducing its quality?

Regards,

[denzjos]

A possibility is using the free program 'Reshade'
https://www.reshade.net

[rich2005]

(12-26-2021, 09:36 PM)rimutaka Wrote: How to increase image size e.g. from 780x1040 to 1920x1080 pxl without reducing its quality?

Generally, no.  Scaling up involves interpolating pixels which introduces some degree of degradation. There are exceptions, for example, pixel graphics scaled up  with no interpolation.

I am sure someone will come along recommending XYZ.com that promises free super on-line results. However this is a Gimp forum for Gimp answers.

You can upscale your 780 x 1040 pix image but now we come to naming conventions  width by height.
1920 x 1080 is 'landscape' while 780 x 1040 is 'portrait' (A) better if it is 1040 x 720   (B)

   

..and there is the question of aspect ratios, they are not the same. You can upscale to fit the height and introduce some vertical borders or upscape  to the width and make an image with a greater height.

   

Whichever way you go it is Image -> Scale Image  see: https://docs.gimp.org/2.10/en/gimp-image-scale.html
Then depending on the result sometimes a small amount of sharpening.

[rimutaka]

Hi,

Thank you for info.

Regards,

[meetdilip]

I think there was an " Enlarge and sharpen " option somewhere in my " Filters " menu. Unable to find it now.

[rich2005]

It is the plug-resynth-enlarge.py plugin ("Enlarge image and synthesize to sharpen.")

I can not really recommend it these days, it does date back to 2010, and there are better options for Gimp 2.10

I have in the past compared many of the 'convenience' options. The Gimp ML plugin, the ReShade program, various g'mic filters, ImageMagick, XnView. Not much difference between any of them and basic Gimp tools. Much depends on how horrible the source image is, but great if you are not bothered about how Gimp works.

Gimp resize using NoHalo interpolation is basically very good. Depending on how bad the original image is (for example, jpeg artifacts) a small median blur for smoothing, then upscale resize, then a sharpen with wavlet-decompose can give a decent result.

...but going back to the original question increase image size ... without reducing its quality? Whatever method used, is guessing pixels and there is some degradation.

edit: you can get the python-resynth plugins here: https://www.gimp-forum.net/attachment.php?aid=6497

[rickk]

Rich:
Thought I'd give the python-resynth plugins collection a try. All seem to work, except can't find plugin-resynth-fill-pattern in the menus. Where does that show up?

[rich2005]

Find it bottom of the Edit menu.

If you use an 'ad-hoc' pattern you have to add it to the patterns folder (and refresh), so the plugin dialogue can find it.

Time to call it a day You can of course use the clipboard pattern

...bye....

[rickk]

(12-28-2021, 09:14 PM)rich2005 Wrote: Find it bottom of the Edit menu.



...bye....

Much  obliged.  As you've stated a number of times, the plugins other than the two "heal" tools, have marginal value.   But, it's nice to have the full set at my fingertips, rather than what someone else thought I "deserved".
Thanks again