how do I relate image size to photo size

Discussion in 'Australia Photography' started by Troy Piggins, Jan 29, 2008.

  1. Troy Piggins

    Troy Piggins Guest

    I don't get many photos printed, but there are a couple I would
    like to get printed out now. I think Harvey Norman prices are
    reasonable. Not sure how they compare quality-wise, but I'm not
    printing commercial type photos so I think they'll be good enough
    for little ol' me.

    So if my original image size is 3504x2336, what max size photo
    could that print without being "pixely"?

    And what size would a 1280x853 image print with comparable
    quality?

    What sort of DPI do photos print at so I can calculate myself?
     
    Troy Piggins, Jan 29, 2008
    #1
    1. Advertisements

  2. Troy Piggins

    Colin_D Guest

    The generally accepted standard for good prints is 300 ppi (not dpi)

    So if you divide the pixel count by 300 you will get the size in inches:

    3504/300 = 11.68 inches by 2336/300 = 7.79 inches without interpolating
    your image.

    You can work out the 1280*853 yourself.

    Note: Images are always expressed as pixels per inch - ppi. Printers
    print dots of ink, so the resolution of a printer is so many dpi. My
    Canon i9950 prints at 4800*2400 dpi. When fed with a 300 ppi image, it
    will use 16 ink dots to make one image pixel (4800/300 - 16)
    horizontally, and 8 dots vertically (2400/300). So one image pixel is
    made up of 16*8 = 128 individual ink dots.

    Colin D.
     
    Colin_D, Jan 29, 2008
    #2
    1. Advertisements

  3. Troy Piggins

    Mike Warren Guest

    If you allow 150 to 200 pixels per inch or greater you'll get
    reasonable results.
     
    Mike Warren, Jan 29, 2008
    #3
  4. Troy Piggins

    Troy Piggins Guest

    * Mike Warren is quoted & my replies are inline below :
    OK thanks.
     
    Troy Piggins, Jan 29, 2008
    #4
  5. Troy Piggins

    Mr.T Guest

    And 250-300 PPI for good results.
    Any more than that and they will usually be resampled before printing
    anyway.

    MrT.
     
    Mr.T, Jan 29, 2008
    #5
  6. Troy Piggins

    Rob. Guest

    But don't depend on that as I have 3000x2000 images printed at 1 x 1.5
    mtrs (with excellent results), which is dependent on the printers raster
    program.

    I suggest you have a look at a crop at 6x4 or 8x10 and you will have a
    better idea just how far you can push the pixels.

    You may find several conspiracies on the subject especially from that
    1001 person whoever they are now :)

    r
     
    Rob., Jan 29, 2008
    #6
  7. Troy Piggins

    Troy Piggins Guest

    * Colin_D is quoted & my replies are inline below :
    Thanks for the detailed explanation Colin.
     
    Troy Piggins, Jan 30, 2008
    #7
  8. Troy Piggins

    Mike Warren Guest

    Hi Colin,

    I notice your message didn't show up for quite some time. I had the
    same problem with Terranews but have now solved it. Email me (remove
    the spam trap) if you want to know how.

    -Mike
     
    Mike Warren, Jan 31, 2008
    #8
  9. Troy Piggins

    Mr.T Guest

    What does "straight from the camera" mean here? Many camera's including
    DSLR's, can't even manage an 8*10" print at 300PPI, let alone anything
    bigger! Most would be far more than that for 6*4" prints, but offers little
    advantage at that small size anyway.
    Post processing will usually improve the result over that "straight from the
    camera", unless the person is incompetent. Remember not everyone is silly
    enough to shoot JPEGS! (I assume you are indicating processing and resaving
    may reduce the quality of an already compressed print)
    Of course it also depends on your definition of "normal viewing distance".
    This will usually be different for a 4*6" print than for a 1*1.5 metre
    print, and I'm talking actual viewing angle here, not just measured
    distance. It is "usual" IME to view a big print at a relatively closer
    distance than a small one, regardless of theory. It's easy to examine
    smaller details on big prints and sometimes difficult to get far enough away
    to compare with a small print, (assuming anyone would actualy want to do
    that) which cannot be critically examined by most people without a
    magnifying glass in any case.

    And there is often a good reason to blow prints up, you often WANT to see
    the fine detail not readily apparent on a small print.

    MrT.
     
    Mr.T, Feb 2, 2008
    #9
  10. Troy Piggins

    k Guest

    | Mike Warren wrote:
    |
    | > Troy Piggins wrote:
    | >
    | >
    | >>I don't get many photos printed, but there are a couple I would
    | >>like to get printed out now. I think Harvey Norman prices are
    | >>reasonable. Not sure how they compare quality-wise, but I'm not
    | >>printing commercial type photos so I think they'll be good enough
    | >>for little ol' me.
    | >>
    | >>So if my original image size is 3504x2336, what max size photo
    | >>could that print without being "pixely"?
    | >>
    | >>And what size would a 1280x853 image print with comparable
    | >>quality?

    (1280/300 = 4.27 inch) x (853/300 = 2.84 inch)


    | >>What sort of DPI do photos print at so I can calculate myself?

    straight from the camera, 300 ppi (not DPI)


    | > If you allow 150 to 200 pixels per inch or greater you'll get
    | > reasonable results.





    | But don't depend on that as I have 3000x2000 images printed at 1 x 1.5
    | mtrs (with excellent results), which is dependent on the printers raster
    | program.


    yup, the printer RIP has a lot to do with the final image and as a general
    rule 300 PPI is what you can safely aim for straight from the camera, for a
    print to be viewed at the 'normal' viewing distance.

    of course it depends on ones eyesight and a 150 ppi image may look wonderful
    to a person with poor eyesight, and for someone like my good wife who's
    legally blind without her coke-bottles, 50 ppi would probably suffice ;)


    karl
     
    k, Feb 2, 2008
    #10
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.