Quality, Print Resolution, and Format

Discussion in 'Beyond the Basics' started by Moglex, Oct 28, 2015.

  1. Moglex

    Moglex TPF Noob!

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    This is quite an involved question, so I apologise in advance if it seems to ramble a bit.

    Let's start with some history:

    Many (many, many) years ago, before anyone had even thought about digital imaging, I used to read photographic magazines. Lots of them. These magazines had vast numbers of images of A4 or A5 size.

    At these relatively small sizes it was, generally, very easy to spot which images had been taken on MF, which on 35mm and (very occasionally) which on 5x4. The larger images were (again, generally) technically superior to the smaller. And the effect was not that subtle.

    Fast forward to the present day.

    It seems to be pretty much accepted wisdom that there is no point in printing images at higher effective resolutions than around 300 RCDPI (Resolved Colour Dots per Inch). Indeed, it's generally pretty hard to even find out what the RCDPI resolution of a printer or processing lab.

    Now, the puzzle is this:

    There are 35mm cameras available with horizontal resolutions of 6000 or greater. Indeed, most decent modern cameras will approach this. This means that you can produce a 20" print with no resampling 'enlargement' necessary.

    This seems to imply that with modern digital technology there would be no advantage to MF for any print that is not greater than 20" in its longest dimension.

    Obviously, there are issues other than simple resolution to consider, but given that it seems unlikely that the vast majority of printed output used a resolution greater than ~300, there is not that much scope for anything other than very minor improvements using MF.

    So, finally to the question:

    What has happened to the quality difference that used to be clearly visible in small prints when it was all emulsion and 'analogue' processing? Have we lost something by going to digital processing that no one has really noticed (even though it stuck out like a sore thumb half a century and more ago)? Or am I missing something fundamental in my analysis of printing resolution?


     
  2. KmH

    KmH In memoriam Supporting Member

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    Inkjet printers do indeed have a specifications defining their maximum DPI.

    Note that it takes many dots, usually a minimum of 3 dots, to print 1 pixel.
    How many dots it takes to print a pixel is a function of how many colors of ink the inkjet printer uses, and what type of print head the print device uses.

    Consequently print resolution/print size (input files) is about PPI (pixels per inch), not DPI (dots per inch). DPI is an output file specification/property.
    Also print resolution is a function of both PPI and the image resolution (pixel dimensions)

    It has been determined that the maximum PPI value the human eye can see image quality differences is about 360 PPI.
    In other words, printing an image that has more than 360 PPI does not result in any improvement the human eye can detect.

    IMO the industry shies away from using the proper terms when applicable because the industry assumes most consumers can't be bothered to understand the differences.

    The 300 PPI so often quoted as the necessary print resolution is a gross oversimplification because print resolution should change as viewing distance changes with print size.

    High image quality large prints can be printed at a print resolution lower than 300 PPI because large prints are viewed from a further distance.
     
    Last edited: Oct 28, 2015
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  3. Bebulamar

    Bebulamar No longer a newbie, moving up!

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    No I don't think we lose anything. If you can't tell the different between formats then it's a gain that's not losing anything.
     
  4. soufiej

    soufiej No longer a newbie, moving up!

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    "Obviously, there are issues other than simple resolution to consider ... "

    That's your answer to your own question.

    As has been pointed out, your post does seem to mix a few disparate concepts into a theory which has no defined limits.

    Therefore, please define "resolution".

    After that ...

    First, are you subjective personality? Someone who feels what you perceive is what is and other information is irrelevant or even distracting? Where do you feel "resolution" occurs? On a page or a disc? Within a circuit? Or, does it all happen in your mind?

    Or, are you a purely objective type who defines performance by way of set group of specifications and measurements not always associated with real world use? Does the shape of a square wave interest you?

    On a similar front, have you ever experienced a 78 RPM monoaural recording reproduced on a truly excellent music system? (I assume you might have since the idea of digitizing an image goes back well over 70 years prior.)

    It is simply a fact in analog recording that higher recording speed equals higher potential "resolution". Just as it is a simple fact in digital that higher sampling rates provide greater opportunity for a more accurate reconstruction of the original signal. Of course, then come all the other circuits and actions involved in creating "resolution".

    Which is the better way to listen to music?

    Head over to the audio forums and find out. You can, just as they have, engage in this debate for decades.
     
  5. KmH

    KmH In memoriam Supporting Member

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    For printing using an inkjet printer there are 3 resolutions that need to be considered:
    1. Image resolution - the pixel dimensions of the photograph.
    2. Print resolution - pixels per inch (PPI) and image resolution.
    3. Printer resolution - a function of how many ink colors and the type of print head the printer uses. Some inkjet print heads deliver between 100 and 200 dots per print head (color of ink).

    Chromogenic prints are made on light sensitive paper that is chemically developed, so there is no DPI.
     
  6. dennybeall

    dennybeall No longer a newbie, moving up!

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    Depending on the emulsion you bought, and your skill, depended on the detail you could produce in a print. In the digital world the number of pixels you capture and the print capability of the printer amount to the same thing. Now the critical question is where will you show the picture - print - pc screen - iPhone screen or projected on the wall of the skyscraper?
    With the technology we have we can usually produce any of those if we know what is needed.
    The quality is now more of a choice than a necessity.
     
  7. Miles Farman

    Miles Farman TPF Noob!

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    Good question.

    The answer is quite simple: Grain.

    Although grain could be unobtrusive that didn't mean it wasn't there. That was why, even with moderately small prints, as the format went up, the result, generally, became cleaner and sharper.

    Although I'll probably be lynched for saying this, there is pretty much no point in using MF or larger for photographs intended to be viewed on a monitor or as prints at or below around 12 x 16. Yes, there are exceptions, but generally, there's no point.
     
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  8. Moglex

    Moglex TPF Noob!

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    Thanks, I think you've nailed it. As you say, unobtrusive does not mean non existent.
     

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