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Thread: rescaling a painting?

  1. #1
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    rescaling a painting?

    ok im working on new paint and its 10in x 14in, 200dpi. how large can it be rescaled? Also if you just change the dpi in the middle of the painting does it also change whats been painted atm?
    my work- gusion85.deviantart.com

  2. #2
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    Hi there.

    To get all those realistic painting affects requires a lot of resources. Consequently Artrage is a bit resource intensive. The larger the painting's dimensions and/or dpi, the greater the resources required. The more memory (RAM) you have, the better things go. You'll have to test with your own machine, but somewhere around say 20inches by 20inches and 300dpi certain resource-intensive tools (soft pallet knife, airbrush and roller on the larger width settings) will start to bog down the program to a crawl. Your experience will vary, but it's somewhere more or less in this size that things can become unwieldy. I've done 24 X 36 inch paintings at 200 dpi, but waiting for the brushes to respond isn't something I'll ever do again.

    Artrage does not appear to me to have the best engine for rescaling up more than about 2X. That's true of most programs, it's not peculiar to Artrage. My personal experience is rescaling from 72 dpi to 150 goes pretty well in Artrage if the painting's dimensions remain the same. I've noticed the loss of texture when increasing from 72 to 300 dpi or more.

    If you wish to significantly increase both painting dimensions and dpi (ppi) I advise using third party software on an exported png (or PSD or TIF) file after your painting is completed. The free program Infranview does a reasonable job rescaling up to maybe 3X in both dimension and dpi, results varying considerably depending on the material in the source file. PhotoShop of course does a reasonable job too. But neither of these programs are outstanding and artifacts are common.

    If your up-rescales are critical and you need very large size increases, the only GREAT product out there is Photozoom (version 3 just released yesterday). It's expensive at US$219 and only does this one thing. But the results are remarkable. You can make huge rescales up (1million by 1 million pixels.) It's THE program for regular and critical rescaling-up requirements.

    After some experimenting in Artrage, I've settled on creating my paintings at 150 DPI at never more that 20 x 20 inches. I then use Infranview or Photozoom to blow up the exported png for printing at commercial ink-jet printers. Photozoom is the far far far superior product, but Infranview is usually sufficient if the upscale isn't too great.

    I don't know if this is more or less than you are looking for. But as one who prints my paintings on canvas at larger sizes, this is where I've settled. No doubt others will have some variation in their experience.

    Hope this addresses your question and is helpful.
    Last edited by byroncallas; 07-04-2009 at 05:13 AM.
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  3. #3
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    I'd agree with Byron.
    Photozoom was called S-Spline before..and it was the best image enlarger I've ever used. Much much better than any other option.
    The general rule of thumb I follow is 1:1 size @ 150 dpi or 1:2 size @ 300 dpi.

    I once had 5700X2700 image printed on a canvas of app 6'W X 3'H size, (which works out to be 1:1 @ 75 dpi) without any problems, although it was a 'woodcut' and any jaggedness would be hidden on the canvas. but I've also printed 7200X3600 on paper at 6'WX3'H (which would be 1:1 @ 100 dpi) without problems. but all this was a few years back and the generally the expectations from 'printed' stuff was much lower than now.

    hope this helps.
    The more hair I lose, the more head I get.

  4. #4
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    From my prints that just arrived...
    My latest, Negative Space printed beautifully at 50x60cm - and could have been larger yet - file was a jpeg (the site only accepted those) at 300 DPI, 2100x2500 pixels.

    And Wodland Green was *just* starting to look blurry at 75cm high, with dimensions of about 3000 pixels high, 300dpi
    (but didn't matter at all at that size, as one has to step away to see it anyway)

    ...for an idea of actual size when printed

  5. #5
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    Quote Originally Posted by Flynn_the_Cat View Post
    ...file was a jpeg (the site only accepted those) ...

    Chambersecrets, some further explanation: A high-resolution, high-quality JPEG as the final output file is perfectly acceptable for most all commercial digital printers and is sometimes the only format some will accept.

    JPEG should not be used as a working file. There is some information loss and the likelihood of introducing artifacts with each new save.

    For paintings that will be printed by third parties the best results will be obtained by first exporting the file from ArtRage as PNG, PSD or TIF. These lossless fromats are safe for tweaking and perpetually re-saving. Make all the tweaks, changes, rescalings, and whatever in those formats. When satisfied with the file, save as a low compression (high-quality) JPEG and give it to the printer.

    The jpg file size will be smaller by several multiples and consequently easier for many digital printers to work with. The printer will convert the jpg into whatever formats work best for their particular pre-press and printing equipment. Ironically, many will first convert the file back to PSD to make their own required tweaks for CYMK printing output. It all depends on the printer's equipment requirements. These vary considerably from shop to shop.

    Acceptable rule of thumb: PNG, TIF, PSD for working files. Convert to high-quality (low or no compression) JPG for final output.

    EDIT: Artrage PSD exports preserve layer information for manipulation in Photoshop.
    Last edited by byroncallas; 07-04-2009 at 05:21 AM.
    // "Appreciation fosters well-being. Be well." - Byron
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    My ArtRage Paintings Here
    // My Comprehensive AR4 & 3 Thread Here
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  6. #6
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    this is a ton of info. thanks alot. I can see how this can get very complicated but i think i have a general understanding now. the painting im working on 10x14 200dpi im only wanting it to be around 2 to 2 1/2 times larger so i think this will be ok and not blur or disropted the image. Really thanks alot from everyone. Also please dont hesitate to tell me anything else you can think of.
    my work- gusion85.deviantart.com

  7. #7
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    Quote Originally Posted by byroncallas View Post
    For paintings that will be printed by third parties the best results will be obtained by first exporting the file from ArtRage as PNG, PSD or TIF
    However, ArtRage has a bug which sets DPI at a lower rate when you export it. (I *think* it's actually a set rate fir each type - 96dpi for jpeg, for example).
    The only one that will keep it at 300 DPI is the PSD (and this is what you want for pritning, ideally).
    You can convert it to other formats in GIMP, if you don't have Photoshop.

  8. #8
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    Quote Originally Posted by Flynn_the_Cat View Post
    However, ArtRage has a bug which sets DPI at a lower rate when you export it. (I *think* it's actually a set rate fir each type - 96dpi for jpeg, for example).
    The only one that will keep it at 300 DPI is the PSD (and this is what you want for pritning, ideally).
    You can convert it to other formats in GIMP, if you don't have Photoshop.
    Flynn, I think it's fair to say this is "sorta" true, but not exactly. I wouldn't mind having someone on the Rage team weigh in here to say what's going on, but it's not exactly a rescaling down of the file from 300dpi to 96dpi, etc. If you look at that 300dpi exported jpg that seems to now be 96dpi, you'll find that the printing dimensions have INCREASED proportionally. All that is required is to reset the file to the original printing dimensions and you're right back at 300 dpi. No real rescaling or resampling seems to have taken place, no information seems to have been added or subtracted. The total pixel (or dot) count seems to remain unchanged. I am not certain, but I think there are interpretations going on between programs reading dpi vs. ppi settings, but I remain uncertain.

    Further, I've noticed that different programs will open the AR exported file at different dpi/ppi readings. On my computers, an exported AR png 300 dpi file will open as 96dpi in Infranview, 200dpi in Paintshop Pro and 72 dpi in Photozoom. In all cases the printing dimensions are scaled proportionally so that total pixel (or dot) count remains the same. Resetting the printing dimensions to AR's original dimensions restores the dpi to 300 in all three programs.

    If anyone on the Rage team reviews it would be helpful to have their perspective. I've gotten used to it and just make the necessary adjustments in Photozoom, Infranview, etc. when preparing files for printers. But it seems a bit much and requires paying attention to what's going on.

    As an aside, if a file doesn't require Photoshop manipulations I don't export to PSD. Photozoom doesn't support the format. PSD files are best converted to PNG or TIF if Photozoom is used for doing huge blow-ups. You need Photozoom if the rescaling-up is very large.
    // "Appreciation fosters well-being. Be well." - Byron
    //
    My ArtRage Paintings Here
    // My Comprehensive AR4 & 3 Thread Here
    64 bit Win8Pro, 16GB Ram, Intel i7 Quad Core - 8 threads; Wacom Intuios 4

  9. #9
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    When we export any file format other than PTG or PSD we don't save any dpi setting. Any changes you see between the dpi value of your painting in ArtRage and the value you get when you open an exported painting in another application are entirely due to either your OS image format handler (we use the OS to export files on both Windows and OSX) or the application you are using to import, we don't touch it. This is why we don't treat this as a bug in the product.

    The number of pixels in the image isn't changed however, so you lose no data even if you have a PTG at 300dpi and when you export a PNG it comes out at 72dpi, the image is exactly the same but it's print settings may need to be adjusted in the application you use to import it.

    We suggest you use PSD if you want to export and have the exported image remember the DPI value you set in ArtRage. But if your format doesn't remember it, most applications that do printing should allow you to reset the DPI value without changing your image pixel content.
    Matt
    ArtRage UI
    Ambient Design.

  10. #10
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    Thanks Matt for the clear technical explanation. It makes sense of my experience, i.e. there is no pixel loss in the exported image.
    // "Appreciation fosters well-being. Be well." - Byron
    //
    My ArtRage Paintings Here
    // My Comprehensive AR4 & 3 Thread Here
    64 bit Win8Pro, 16GB Ram, Intel i7 Quad Core - 8 threads; Wacom Intuios 4

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