Thank you Austin. Many of the points you make were my impression also.
The statements were not clear or precise with respect to at what point in
the printer driver processing of data the 720 figure is relevant (I chose to
ignore the wide format models in my comments) or the resampling by the
printer driver takes place. The way it was presented leaves the language
and argument open to interpretation; but in fairness to Kennedy, I do not
think that he was addressing the exact same issues that are in question in
this thread and that what some are taking as proof of their arguments on
those points is not actually proven, although on the surface it appears to
somewhat agree with their statements to a limited and qualified extent.
To be clear, I did not cite or provide the quoted materials, Paul, I
beleive, was the one who said that posts on the Epson lists proved his
points to which I responded that I was unfamiliar with those posts even
though I did belong to those lists. Bob Frost thne supplied the quoted
materials that were being referred to and may have been the one who
emphasized that they were using ppi and not dpi in the post.
Personally, while dpi, ppi, spi, etc. are all terms of art and technically
related to very different things, they are used so loosely in the everday
world and so interchangably, that I no longer get bent out of shape when I
see one used where another may be more appropriate. Thus, I am not getting
picky about the use of this terminology and allow that Kennedy may have used
the terms interchangably to basically stand for a per inch indicator of
reolution be it dots, samples, or pixels. I do believe that as a matter of
course all the references to resolution associated with their printers and
maybe even their scanner made by Epson are in terms of dpi not ppi. This
may be why the post tends to use the two interchangably. At one point, I
may have suggested that Epson referred to the 720, 1440, 2880 figures of
resolution in terms of dpi and not ppi or spi because they were meant to
give approximate halftone resolutions of the finished print after dithering
and reflected something equivalant to the traditional line screen factor in
determining halftone resolutions of traditionally printed materials. This
may explain why Bob emphasized that the post he furnished used ppi.
filmscanners_owner@halftone.co.uk <> wrote:
> Hi Laurie,
>
>> Kennedy McEwan published the 'proof' and Epson also state the facts
>> in one of their technical support documents -
>> . This says
>> quite clearly that the large-format printers resample to 360 ppi
>
> Actually, it does not say that. It says 360 DPI...NOT "ppi"...so I'm
> not clear that this is exactly what they are talking about, and if it
> is, they should have said PPI, as you did. Here is the quote:
>
> "All Epson large format printers use 360dpi as the input resolution
> (this is the resolution data is rasterized at), and therefore when
> printing from Photoshop, the maximum page length you will be able to
> output to any Epson Large format printer using the standard print
> driver would be 83.33 inches (30,000 / 360dpi)."
>
> So, though I can "interpret" that what was stated "may" mean that the
> standard Epson print driver re-samples the input data to 360PPI, that
> is not what it actually says, so I'm left wondering what, exactly,
> they were really saying. I'm not saying it's true or isn't, but that
> the "evidence" is flawed and certainly open to a differing
> interpretation...
>
> Also, at the end of this paragraph, they have a simple arithmetic
> error...they meant "41.67 inches (30,000 pixels / 720dpi)"...instead
> of " / 360"...but...they still are confusing DPI and PPI in this
> paragraph, yet they use "300ppi" (NOTE ppi) in the first sentence of
> this paragraph, so they clearly know there is a difference. This
> leads me to believe they may be talking about something different
> than the actual input data gets resampled to 360/720 PPI, but that
> the dither algorithm works at that resolution, and has nothing to do
> with input data resampling.
>
> Austin
>
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