Two ways of looking at how large to print

Discussion in 'Digital Photography' started by Scott W, Apr 9, 2005.

  1. Scott W

    Scott W Guest

    In another thread the question came up as to how large can you make a
    print from a give size image, in this case from a 3.2 MP camera.

    There are two ways to look at how big a print should be made, both are
    correct under some circumstances. On one hand you might want the print
    to be just as sharp as you can get it, in this case you would want to
    print at 300 dpi and some people would say even higher. This would
    limit a 3.2 MP image to about a 4 x 6 print. But the other way to look
    at it is that the photo has a certain amount of detail in it and you
    might want the people looking at the print to be able to see all the
    detail that is in the photo. The human eye has a hard time seeing low
    contrast details that are small, so printing the photo large will make
    more visible to the viewer.

    To many photographers the sharpness of the print it critical and they
    are reluctant to make prints that would reduce the resolution below 300
    dpi. But for any give photo printing it larger will make a print that
    almost all people will prefer to look at. I have seen this over and
    over again, I used to make small prints from my Nikon 995 (3.2 MP
    camera) that where very sharp and I would also make 8 x 10 prints of
    these same photos. People overwhelmingly preferred to look at the 8 x
    10 prints.

    So what resolution is right for a print depends on the circumstances,
    if you know you are going to be making 8 x 10 prints, then you are best
    off using a camera that has somewhere around 8 MP. But if rather you
    have a photo form a given camera and you want to make the best looking
    print from it then you would print larger, printing at a DPI of
    somewhere between 150 and 200 seems good.

    Just to be clear I am not saying that for a given size print 150 dpi
    will look better then 300 dpi, far from it. What I am saying is that
    for a given digital image printing at it 150 to 200 dpi will produce a
    print that most people will enjoy looking at more then a smaller print
    made at a higher dpi.

    I should also point out that the amount of noise in a photo will
    greatly effect the optimum size to print it at, more noise smaller
    print. And of course it always help if the photo is in focus.

    Scott W, Apr 9, 2005
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  2. Scott W

    ecm Guest


    Yes, you're right, of course. But, it also depends on what the
    photographer is trying to convey in the print.... the print is just a
    logical continuation of the process of capturing a photographic image,
    and the detail on the print is as important as the lighting, exposure,
    and medium it's captured with.

    I often print my vacation snapshots at 200 dpi after cropping, and it
    looks great at 4X6 - it's a memory, really, it doesn't matter if it's a
    bit fuzzy as long as it evokes the right emotions. If I want to hang
    something on the wall, though, I want that "art photo" detail and
    crispness, so that a viewer can look at it from 6 feet, 2 feet and even
    6 inches and see something new each time. Take a really close look at a
    good quality Ansel Adams reproduction sometime - you'll see what I'm
    talking about. Mr. Adams was as much a master in the darkroom as he was
    behind the camera....

    ecm, Apr 9, 2005
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  3. Scott W

    mike regish Guest

    I'm interested in this too. When I open a 6 Mb image in PS and click on
    "image size", it comes up at 41"x27" and 72 dpi. I usually crop at a 8x10
    ratio, resize to 8"x10" and resample to 300 dpi. Originally, it's about
    3000x2000 pixels.

    Why does PS default to such a large dimension (in inches)? My printer only
    does 8x10, but I'd really like to get one blown up to that 41x27 sometime,
    just to see what it looked like. I just resampled the original at 300 dpi
    and it was something like 298 Mb and 12,000 pixels wide.

    Also, I'm getting from this that the camera will only deliver a certain
    limited dpi depending on the camera's MP. How does PS resampled dpi relate
    to what the camera can deliver. Does it fake some pixels or something?

    mike regish, Apr 9, 2005
  4. Scott W

    Scott W Guest

    72 dpi is there for historical reasons, the screen resolution of the
    very early Mac was at 72 dpi. This is still a number that is commonly
    used as a good average screen resolution. So if you are looking at
    your photo on the screen at full size it will in fact be huge.

    It is easy to set the dpi to anything you want without effecting the
    photo, under resize uncheck the resample checkbox and then simply type
    in the new dpi that you want.

    Most of the time when you get a photo printed the dpi that is imbedded
    in the photos is not used to make the print, the program that is doing
    the printing will scale the photo to fit the page. Some programs allow
    you to either print at the given dpi or to scale the photo to fit the

    When you get your photo printed outside at someplace like Wal Mart or
    Costco they are always scale to fit the size of the paper being printed
    on. So I can take the exact same photo to Costco and get two print
    from it, one a 4 x 6 and the other a 12 x 18 and both of these will
    print fine because the photo printer that they use will scale the photo
    for me.

    Scott W, Apr 9, 2005
  5. Scott W

    paul Guest

    I agree. 3MP photos don't look better than 6MP at that size but they
    definitely look better than 4x6's! I made a bunch of 8x10's from my 3MP,
    some even cropped and people love them. I did a tiled 16x20 & it looked
    great (from a distance).
    paul, Apr 9, 2005
  6. Scott W

    Ron Hunter Guest

    Because you have your display set at 72dpi. Most monitors can be set to
    96dpi (or higher), and the rendering will make a smaller picture. It is
    just spreading the pixels out at the setting for dots/inch for your
    display device. To print, you need to specify a higher DPI so that the
    size will be what you need. Most programs do this math FOR you, which
    is why I rarely print from Photoshop Elements.
    Ron Hunter, Apr 9, 2005
  7. Scott W

    Bubbabob Guest

    You'll get much better resizing in photoshop. The native resolution of
    CostCo's QSS-3101 printers is 320 ppi.
    Bubbabob, Apr 9, 2005
  8. Scott W

    Chris Brown Guest

    Indeed. I have yet to have the "Image Size" dialogue trip the shutter

    You can also rescale the dpi without affecting the image, which is very
    handy. ;-)
    Chris Brown, Apr 9, 2005
  9. Scott W

    Justin Thyme Guest

    Ahh, the old dpi confusion issue. A digital photo does not have a dpi
    resolution, it has pixels. A 6MP digicam has roughly 3000x2000 pixels. DPI
    settings are irrelevant, 3000x2000 pixels is how much detail is in there.
    DPI only comes into play when the image is viewed - whether that be on a
    computer monitor or on a print. Computer monitors are considered to have on
    average 72dpi, so when photoshop says an image is 72dpi, it only says that
    because it is displaying it on a computer screen. If the image is 41"x27" @
    72dpi, what photoshop is really saying is "if you want to view this image so
    that 1 pixel in the original matches 1 pixel on your monitor, and assuming
    your monitor is at the average 72 dpi then the image will measure 41inches x
    27inches". There is no need, and no point, to resize the image just to
    resave it again. Ignore the size in inches and dpi, and work only in pixels
    at this level. Then, if and when you want to print the image, resize to the
    target size and resolution.
    Justin Thyme, Apr 10, 2005
  10. Scott W

    mike regish Guest

    Thanks. That makes it much more understandable to me. I have been resizing
    and resampling to 300 dpi for prints, but couldn't understand how that
    related to what was on the monitor.

    Thanks again.

    mike regish, Apr 10, 2005
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