Image resolution for print: maximum/appropriate

Discussion in 'Design and Graphics' started by zarusoba, Oct 11, 2008.

  1. zarusoba macrumors 6502

    Joined:
    Feb 3, 2006
    Location:
    Australia
    #1
    What's the maximum print resolution these days?

    And what's an appropriate print resolution for the image I'm working on at the moment? It's a greyscale illustration that I did in pen and ink originally, and I'm now working on it in Photoshop. It was scanned at 400 dpi.

    Thanks.
     
  2. Jim Campbell macrumors 6502a

    Jim Campbell

    Joined:
    Dec 6, 2006
    Location:
    A World of my Own; UK
    #2
    As machines get faster and more powerful, I've noted a lot of what I've come to call "DPI Machismo" creeping in, that is: if the image isn't 1800dpi with a file size of ~3Gb, it can't be any good. This is, for the record, utter nonsense.

    300dpi at actual, printed size will be absolutely fine for most purposes. If it's going to be printed on good quality, bright white stock with a nice finish (or if you want to give a bit of leeway for scaling) you might want to think about 600dpi. Anything higher is just a waste of disk space and clock cycles.

    On the other hand, is the image simple enough to trace then add grey tones in Illustrator? The reason being that an Illustrator EPS is resolution-independent and DPI will cease to be an issue.

    Edit to add: when finished, make sure to save your image in a lossless, print friendly format. TIFF with LZW compression gives compact files with no loss of quality.

    Cheers!

    Jim
     
  3. zarusoba thread starter macrumors 6502

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    Feb 3, 2006
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    Australia
    #3
    Thanks for the tips, Jim.


    In this case the image is too complex for Illustrator. Cheers.
     
  4. dazzer21 macrumors 6502

    Joined:
    Oct 18, 2005
    #4
    Typically speaking, the old fashioned lpi vs dpi rule (dpi = lpi x2) is used here, although pretty much all publications request final print resolution of 300dpi anyway. For poor quality Newspaper reproduction, if the publication is printed using a halftone screen of 60 lines per inch, a scan resolution of 120 dots per inch will suffice (although it's always best to factor in a little more, so 150dpi will do). Magazines typically print at 150lpi, hence the request for 300dpi images - some may be 175lpi in which case, 350 will do, but it's always better to err on the side of (just a little) excess.

    As Jim mentioned, DPI Machismo (thanks for that, by the way - I'll use that the next time the agency I deal with gives me 2Gb Illustrator files with images saved at 4500dpi (yes, you read that right!) and expect me to turn the work around in minutes rather than days!) is all too prevalent. Damned Xeon processors...
     
  5. Shoesy macrumors 6502a

    Shoesy

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    Jun 21, 2007
    Location:
    Colchester, UK.
    #5
    How is lzw lossless? Seriously I don't really understand how law works at all. JPEG I get (I think) but lzw I don't really know about :(
     
  6. Jim Campbell macrumors 6502a

    Jim Campbell

    Joined:
    Dec 6, 2006
    Location:
    A World of my Own; UK
    #6
    Well, basically, it is, so does it really matter how it works as long as it is lossless, when JPEG isn't?

    I'm not having a go at you, BTW. This page explains LZW compression:

    http://en.wikipedia.org/wiki/Lzw

    And, I have to say, I don't understand a feckin' word of it. However, I do understand that JPEG compression is a lossy format that sacrifices detail for data compression and LZW is a lossless format that doesn't.

    For me, that's job done!

    Cheers

    Jim
     
  7. panoz7 macrumors 6502a

    panoz7

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    Nov 21, 2005
    Location:
    Raleigh, NC
    #7
    I'm not absolutely certain, but I'm pretty sure that LZW works by replacing large chunks of repeating data with a single reference. For example, in a landscape photograph where the entire sky was blown out and was pure white, instead of recording the color of each individual sky pixel one at a time the entire continuous sky could be recorded at once.

    As for the OP, I was taught to work at 300 dpi for color or grayscale images and 1200 dpi for bitmap.
     
  8. bocomo macrumors 6502

    Joined:
    Jun 29, 2007
    Location:
    New York
    #8
    also depends on viewing distance (if this is a poster/mag page/billboard)...

    for the illustrator/vectors comment-perhaps you could use live trace on a scan of the drawing? just saying maybe it's an option

    for the lossless compression question: think of it this way, if i was packing a suitcase (data in my file) and i wanted it to pack down smaller, i could:

    a) throw some things out that i might not miss (lossy compression)

    or

    b) pack it in more efficiently (lossless compression)

    what the other poster said about it regarding the computer not having to remember the value of many pixels that are the same is right on
     
  9. AlexisV macrumors 68000

    AlexisV

    Joined:
    Mar 12, 2007
    Location:
    Manchester, UK
    #9
    You can't go much wrong sticking with 300dpi for everything apart from when you get above A0, when it's ok to switch to 150dpi.
     
  10. skyton macrumors 6502

    Joined:
    Jan 3, 2005
    Location:
    england
    #10
    exactly this ^

    300 as standard for almost everything
    with a few notable exceptions like very large format printing
    when you get into banner stands they seem to make their own rules up!
    but for everything else - 300
     

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