Sharp artwork upscaling: hq4x? Another method?

Discussion in 'Design and Graphics' started by nagromme, Jul 3, 2012.

  1. nagromme macrumors G5


    May 2, 2002
    I’m trying to help a friend upscale some 1024x768 artwork (iPad paintings) to higher pixel resolutions so it will look better when printed.

    Photoshop’s own scaling + playing with filters and sharpening isn’t good enough. Neither is vector tracing.

    But I see lots of great examples online; the “hq4x” or “hqnx” open source methods look especially nice! But I remember in the early 90s, bitmap art could be printed with similarly sharp but less-advanced upscaling. Even that would be sufficient, but I don’t know what it was called.

    How can I do this kind of sharp upscaling... without compiling source code? Some utility or plugin would be well worth my time. Diving into open source and compilers would not be!

    Thanks for any Photoshop OR non-Photoshop ideas!
  2. jeremy h macrumors 6502

    Jul 9, 2008
    I assume you've tried all the usual Photoshop tricks (changing enlargement mode, doing in several stages etc) and the third party type stuff from companies like onOne?

    Failing those...

    One trick that might work though - and this is something we used to do years ago - get the image output to transparency (say a 5x4) and then get it rescanned to the enlarged size. All a bit analogue ;) but it used to work really well.
  3. nagromme, Jul 4, 2012
    Last edited: Jul 4, 2012

    nagromme thread starter macrumors G5


    May 2, 2002
    Thanks! Yes, I’ve tried all the usual in Photoshop, but the look is just nowhere near as nice as a “real” upscaling algorithm can provide.

    I decided to give GIMP a shot (what a horror :p )—an older version to dodge a recent X11 bug—and I’m on the quest for plugins now. I found a “scale3x” plugin but it really doesn’t work well; maybe it’s meant for 1-bit imagery.

    I can’t believe Photoshop can’t do this kind of scaling natively (or via any plugin I’ve found for that matter)! If it turns out it can, I’ll switch back to PS for this pronto!

    EDIT: Ugh. Nothing seems to exist even for GIMP. No 2xSaI, no Super Eagle, no hqnx, none of the modern upscaling methods I’ve been reading about. Just lots of people on the 'net wishing for them. Oh well!
  4. R1PPER macrumors 6502

    Oct 1, 2008
    There is no such thing as a magic upscale. Just up the res in photoshop and live with the result. all these scale up algorithems might make it 5% better..but ive never ever seen anyone use them and ive been working in creative studios for 15 years.
  5. nagromme thread starter macrumors G5


    May 2, 2002
    So have I, but the example I linked to (and many similar algorithms going back years) does something really useful that IS almost magic for certain kinds of art:

    This method is used to “modernize" old videogame pixel art, for instance. (Not that I agree with that usage since I like those classic pixels just fine.)

    But I can’t find any working plugin for wither Photoshop or Gimp that does any of those. Oh, well.
  6. bocomo macrumors 6502

    Jun 29, 2007
    New York
    those are VERY specific use cases

    what type of artwork are you trying to enlarge?
  7. nagromme thread starter macrumors G5


    May 2, 2002
    Art that would benefit from the algorithms I’m seeking: I posted this very specific question because my use case is very specific.

    But for now, it seems those tools don’t exist except for application developers.
  8. porg macrumors member

    Dec 3, 2008
    A response 4 years later, but maybe still of help.
    There is a pixel art upscaling command line application for the Mac called scale2x.

    Both installation and usage shouldn't be too difficult for graphical users. has a 3 step installation instruction.
    Or only one step if you have the brew package manager already installed:
    brew install scale2x

    And then the command is simply:

    scalex [-k N] input.png output.png

    N defines the scaling factor, which can by any of: 2, 2x3, 2x4, 3, and 4

    So simply type "scalex -k 4 " (without the quotes but with an empty space after the command) then drag and drop your image file onto the Terminal App input prompt once, so that it is set as the input file, and a second time so that it forms the output file too. Then just add "-4x" or "--upscaled" or a similar applicable suffix to the file name end right before the ".png" suffix. Otherwise you would overwrite the input file with the upscaled output file.

    And voila, you have your upscaled file. Hope that I could have been of help.

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