Re: dumb question

Me wrote:
fred@xxxxxxxx wrote:
On Fri, 01 Aug 2008 13:03:08 GMT, "HEMI-Powered" <none@xxxxxxx> wrote:

Andrew Koenig added these comments in the current discussion du
jour ...
"P§³" <xvzex3qtgix@xxxxxxxxxxx> wrote in message news:uktkk.554$Ht4.171@xxxxxxxxxxx

I've been out of photography for many years so this digital
stuff is new to me so please forgive the dumb question. I'm
confused about the maximum image size one can get out of a
camera like the Nikon d700. What's the largest quality PRINT
one can make with this beast.
How sharp do you want the print to be?

The basic image size is 2832 x 4256 pixels, which is 9.4 x 14
inches at 300 dots/inch or 14x21 inches at 200 dots/inch. For
bigger prints than that, you would probably want to use some
kind of dithering/upscaling tool such as Genuine Fractals.

DPI is an incorrect unit designation; DPI is most commonly used for scanning where the hardware scans X dots per linear inch of material, where each dot turns into a pixel. In digital printing or processing, everything is already in pixels and is re-
converted to a spot on the paper, hence the proper units are PPI or Pixels Per Inch.

Wow are YOU wrong!!!

Pixels are reserved for MONITOR DISPLAYS!

Printers are ALLWAYS rated dots per inch! My Dad agrees, and he's been a
printer for 40 years... look up halftone mask...

WRT the OP's question re print size, then:
DPI of inkjet printers (the number on the sales brochure/box) gives a totally unreasonable figure, but my "4800x2400 dpi" printer will resolve about 400 lines per inch horizontally and about 200 lines per inch vertically of dithered half-tones. So, it's potentially around about 600dpi (about double what most commercial wet-process prints are) depending what you measure and how.

That figure is not unreasonable. Good printers print at so many pixels per inch (PPI), the 'native' PPI for the printer; Canon uses 600PPI, and Epson uses 720 PPI. That is pixels per inch delivered to the printer. The printer driver software resamples whatever the actual image PPI happens to be up to the native PPI the printer requires.

The printer, though, lays down on the paper its native dots per inch, DPI, for my Canon it's 4,800*2,400 dots per inch.

This means that a single pixel at 600 PPI will have 4800/600, or 8 dots horizontally by 2400/600 or 4 dots vertically, a total of 32 dots of ink to represent one pixel of the image. The printer will vary the color of each dot to produce the required blend of ink to reproduce the correct image color.

Colin D.
.

Relevant Pages

  • Re: thematic collecting - scanning images of stamps
    ... The encoded result of the scan will be converted on a computer screen to pixels horizontally/vertically depending on the resolution of the screen; in a similar way the printer may use 600/300 dots/inch horizontally/vertically depending on the resolution of the printer head, ... I prefer to use to pixels when I refer to a computer or television screen; and to dots when talking about scanners of printers. ... ppi is the term. ... How is it my Epson shows "dpi" and Wiki siggests dpi is the language ...
    (rec.collecting.stamps.discuss)
  • Re: I have a 30mp camera redux
    ... 360 dpi and 720 ppi on my Epson. ... A computer presents images as a unique number of pixels, ... from not 3 dots of RGB, but from *many* dots of Cyan, ... quality printing at 120 pixels per inch, ...
    (rec.photo.digital.slr-systems)
  • Re: dots per inch?
    ... Is this the same as 350 pixels per inch? ... There will be no doubt another long debate about ppi vs. dpi, ... but yes if they asked for 350 dots per inch it is a very good ... bet that what they really meant was 350 pixels per inch. ...
    (rec.photo.digital)
  • Re: dots per inch?
    ... Is this the same as 350 pixels per inch? ... meanings, but in the photo editors I've used, I can change the PPI ... 11 but leave enough space for the narrower aspect ratio of a 4 x 6. ...
    (rec.photo.digital)
  • Re: National Geographic vs. Canon print paper
    ... For 35mm, most people find that somewhere in the 2500-5000 DPI range better able to extract all the image information available, then resampling down to whatever they think is "right" for their purpose. ... I would call PPI. ... To me, being the simple engineer that I am, when scanning, DPI is the correct term while when printing from an existing image in pixels, then PPI is the right nomenclature. ... If you refer to dots per inch, ...
    (rec.photo.digital)