: How to upscale a non-vector PNG pixel image without lossiness or blur? I see it said pretty much everywhere that you can't upscale a non vector image without some lossiness and blur, but how

@Sarah814

Try to shrink this:



It's easier than making something bigger.

The black outline need some manual work to make it blocky if it's wanted. But test, if this is useful. The white fill should be exact - it's not copied from elswhere, it's from your image, only the anti-aliasing is quessed and taken back. It didn't work perfecly to the outline that had sharp blocky outer edges. I put a new smooth outline.

NOTE: Download this PNG, if you copy and paste it, the result is random. Probably you lose the transparent background.

The receipe:

Your original small r was enlargened to 800% pixel dimensions. There are many good resizing programs that quess the missing details and can take back some obvious anti-aliasing. On1 Perfect Resize was used here. The result:



The outline isn't especially nice, but there was no glue to do it otherwise. The interior was anti-aliased. On1's resizer by default thinks the interior has originally had a sharp edge.

I selected the interior, smoothed the selection (not blurred nor feathered) and painted it full white. Then I took the interior to Inkscape (=Ctrl+C, Ctrl+V)

In Inkscape I traced the interior with default settings. See the following cartoon:




The enlargened r with whitened interior. This was not traced!
The interior after the tracing, turned to black and a thick black stroke was inserted
The interior after the tracing, only white fill, no stroke
this is 3 and 2 piggybacked, the same as already offered to be shrinked


ADDENDUM: On1 Resizer is a high cost program. There's also usable freeware. I have tried Smilla Enlarger. sourceforge.net/projects/imageenlarger/
Its results are a little softer than On1's. But they can be sharpened. Smilla seemingly tries to quess also what's behind the blocky outline of your r. Heres a enlargening result which is made in Smilla and then made sharp in GIMP.

NOTE: This is bitmap, no tracing attempted.

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@Nickens508

You will achieve the best possible result increasing the size of the image so that it becomes 4 times as much. The simple explanation is that doing so, every pixel will be drawn on 4, and there will be no processing or alteration of the image that you can't control. An example of this is seen when projecting an HD image on a 4K screen.

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@Pope1402555

Using Interpolation: None instead of Cubic, Linear, or Sinc gave me the results I was looking for.

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