Digital BW, The Print

----- Original Message -----
From: "Anthony Atkielski" <atkielski@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Friday, August 02, 2002 12:28 AM
Subject: Re: [Digital BW] Storage of digital images


> Martin writes:
>
> > The inks are not opaque, even the pigment inks.
>
> I know.  Neither are offset printing inks.  But for practical purposes,
they
> are generally treated as opaque.  They do not have the transparency of
> dye-sub or chemical emulsions, and I do not see whatever transparency they
> possess ever being used in actual printing.  If inkjet printers had
reliably
> transparent inks, they would print like dye-sub printers, and you'd be
able
> to get a true 2880 ppi on the print.
>
> > So drops of ink can be placed on top of each
> > other to create intermediate tones.
>
> That doesn't appear to be happening on the inkjet prints I've examined.

Anthony,

The only place I don't see that happening in a grayscale inkjet print is in
the very lightest area where a single ink is doing all the work. Even there
I can't distinguish individual dots in the prints from my 1280 even with an
8x loupe so I have to assume that they overlap or are so small it simply
doesn't matter.
>
> > I believe that the inks used in offset printing
> > are quite different from those used in inkjet
> > printers.
>
> They probably are, but a common characteristic between the two is opacity.

As I said I find the grayscale pigment inks quite transparent and the Epson
color dye inks to be completely transparent.
>
> > Your logic is partially correct for something like an
> > image setter or standard laser printer but the fact
> > that the different inks can be overlaid to create
> > different tones or hues, and the use of dither patterns
> > suggests that you can simulate much more than the math
> > implies.
>
> Dithering dramatically reduces resolution, so I don't count that.  Close
> examination of the prints from my 2000P (and indeed of any inkjet prints
> that I've looked at thus far) reveals adjacent dots of ink, not overlaid
> dots of ink.  If you look closely enough, the image always shows a slight
> grain from this adjacent placement, like that of a stochastic halftone
> screen in offset.

Well the point is not to have any visible resolution. I generally cannot
detect the dither pattern in prints off the current generation of Epson
inkjets with either the Epson driver or the Piezo driver. I can see it a bit
in output from the 3000 and 1200 in the upper highlights looking very close.
The 2000P has a larger than average droplet size as I recall. In general the
dither patterns appear to be completely undetectable at "normal" viewing
distances. My 13x19 prints done from drum scans of 4x5 negs show the grain
of the Ilford FP4+ film when viewed with a loupe. If the dither/resolution
is finer than the film grain what more do I need?
>
> In contrast, dye-sub printers overlay transparent inks directly, and the
> prints from my Alps MD-2300 (which unfortunately I no longer use, because
> supplies are scarce and the printer is far too finicky) show razor
> sharpness.  Under the loupe, each pixel is clearly distinct, with its own
> color and intensity, and there is no dithering or grain.  I wish Epson
made
> dye-sub printers--with this quality but with the reliability and
> user-friendliness of other Epson printers.  It's just too much trouble to
> get stuff printed on the Alps, but it sure did a beautiful job--the
results
> could not be distinguished from a chemical print (and would tolerate
> scrubbing under a stream of water without any visible damage).

I have not seen many dye-sub prints but the ones I have seen did not seem to
be any better than a good inkjet print.
>
> > If what you say was correct, I doubt that we would
> > be very pleased with out digital prints, color or B&W.
>
> I'm not.  They look nice from a distance, but they always lack sharpness
> upon very close examination, just like halftone images in a magazine.

All I can say is that something is wrong with the inkjet prints you have
been looking at. If properly done, I have found inkjet prints to equal or
exceed silver prints in terms of sharpness and resolution and do not bear
any resemblance to a magazine line screen image.
>
> > I believe it would be more correct to say that
> > a modern inkjet printer interprets pixel input
> > rather than to say it prints pixels.
>
> That's true, but it is still constrained by the opacity of inks.

The end result it better than the pixel input in that it takes a halftone
and produces a continuous tone.

Martin