Epson printers - 2400 vs. 4800 ??

Mark Anon wrote:

As always it's best to ignore the troll.

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Keep working millions on welfare depend on you

rafe b rafebATspeakeasy.net wrote:

If we all ignore the troll it will go away.
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Keep working millions on welfare depend on you

I'm not a troll. I simply asked a question.


"Frank Pittel" wrote in message
...
Mark Anon wrote:

As always it's best to ignore the troll.

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Keep working millions on welfare depend on you

"Gordon Moat" wrote in message
...

It bugs me about the picolitre usage, when the commercial printing
industry and major paper companies don't use such numbers. Also, while I
managed to get paper samples from Epson, getting specifications anything
near like what I would get from International Paper, Sappi, Weyerhaeuser,
or any other paper company didn't happen . . . the best I could manage was
incomplete data on weights, largely without whiteness, brightness, nor
surface finish. Sorry for the rant.


Offhand, why would (or should) Epson or Canon or HP be
constrained to use specification standards from the offset
printing industry?

The user base, technology, and intended application are
completely different.


rafe b
www.terrapinphoto.com

In article n5mvf.7911$V.719@fed1read04, Mark²
writes
Kennedy McEwen wrote:
In article w9bvf.7874$V.6727@fed1read04, Mark²
writes

I contend that there isn't ANY media capable of showing a benefit of
dpi that high.

There are plenty of such media, they just aren't papers. :-)

Who said anything about papers?
I still challenge anyone to produce evidence that ANY media will show the
useful exhibition of 9600dpi from an ink jet type printer.

You didn't say anything about injet printers either! ;-)
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's ****ed.
Python Philosophers (replace 'nospam' with 'kennedym' when replying)

In article , Stanislav Meduna
writes
Mark² wrote:

I still challenge anyone to produce evidence that ANY media will show the
useful exhibition of 9600dpi from an ink jet type printer.

The dpis aren't there because someone might actually see
the resolution, they are there because the inkjet dot
is not a '24-bit' dot. The printer has to dither - and the
more dpi, the better it can do this.

So you have to divide the stated dpi by the number of inks
and then further by number of 'levels' you want to have
from one ink (depending on whether the inkjet can modulate
the size of the dot or not this really matters or not).
A 5760x1440 dpi printer with 8 inks is in reality 720x1440
for one ink color. Divide the 720 by two and you get 360 lpi -
something that is not far away from what one can see with
bare eye.

Correct in principle, but not in detail. Your estimate of actual
performance is widely inaccurate. What matters is the amount of density
noise that you are prepared to tolerate, which is infinite beyond visual
acuity and steadily reduces to around 40dB at very coarse detail. The
specific dither process used determines the transition between these two
requirements. Even a meagre 1440x720dpi 4 ink printer is capable of
resolving 720ppi detail, albeit at high noise levels. However, 720ppi
is well beyond visual acuity limits so the noise at that extreme is only
relevant when viewing under magnification. At typical visual limits,
the noise can be almost acceptable, even if not quite photo quality,
depending on the dither algorithm used.
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's ****ed.
Python Philosophers (replace 'nospam' with 'kennedym' when replying)

rafe b spake thus:

"Gordon Moat" wrote in message
...

It bugs me about the picolitre usage, when the commercial printing
industry and major paper companies don't use such numbers. Also,
while I managed to get paper samples from Epson, getting
specifications anything near like what I would get from
International Paper, Sappi, Weyerhaeuser, or any other paper
company didn't happen . . . the best I could manage was incomplete
data on weights, largely without whiteness, brightness, nor surface
finish. Sorry for the rant.

Offhand, why would (or should) Epson or Canon or HP be
constrained to use specification standards from the offset
printing industry?

The user base, technology, and intended application are
completely different.

Yes, but the paper specs still have the same relevance; though a
different printing method is being used, the paper still has a certain
brightness and surface finish, and therefore wouldn't it be nice to be
able to compare it to, say, Sappi 80 lb. smooth offset in terms of these
characteristics?


--
The only reason corrupt Republicans rule the roost in Washington
is because the corrupt Democrats can't muster any viable opposition.

Mark Anon spake thus:

I'm not a troll. I simply asked a question.

He's trying to get you to ignore someone else (you-know-who) that he
considers a troll (basically because he doesn't like him), a behavior
that I find far more annoying than the alleged "trolling". So just
ignore *him* (Pittel) and continue your normal posting.

"Frank Pittel" wrote in message
...

Mark Anon wrote:

As always it's best to ignore the troll.


--
The only reason corrupt Republicans rule the roost in Washington
is because the corrupt Democrats can't muster any viable opposition.

"David Nebenzahl" wrote in message
s.com...


Yes, but the paper specs still have the same relevance; though a different
printing method is being used, the paper still has a certain brightness
and surface finish, and therefore wouldn't it be nice to be able to
compare it to, say, Sappi 80 lb. smooth offset in terms of these
characteristics?


If you want nicely-specified inkjet papers, have a look he

http://www.magicinkjet.com/products/printers_by_man.epl

The technology of current "inkjet papers" is pretty impressive.
These things we think of as strictly two-dimensional sheets
turn out to be complex laminates of numerous layers.


rafe b
www.terrapinphoto.com

Mark² wrote:
I still challenge anyone to produce evidence that ANY media will show the
useful exhibition of 9600dpi from an ink jet type printer.

Don't confuse dpi [random tiny dots] and pixels [resolved information].

300 pix/inch is what most printers actually provide. Try printing a
test target and look with a loupe. For all practical purposes
300 pixels/inch is really all that is needed.

9600 dpi at 300 pix/inch gives 1024 dots/pixel [the number of dots
in a square pixel is the square of the number of dots along each side].
If we print only magenta dots then there can 1024 shades of magenta.
256 shades, the minimum for colors to look smoothly gradated, requires
8 dots/pix-inch resulting in a true 1200 pixels/inch.

With a 1200 dpi printer at 300 pix/inch there are 16 dots/pixel
and only 16 shades of a pure primary color are possible. To overcome
this limitation the printer blends adjacent pixels to make intermediate
shades and the printer is really doing ~75 pix/inch to get saturated
colors. The printers also mix dot colors [pure magenta at 50% will have
yellow and cyan dots in it] to make more shades of a color
but the color is now unsaturated.

As a result, until high dpi printers became available one had a choice
of snappy colors at a low resolution or sharp pictures but blah colors.

This is also why black & white is so hard to do will with an ink-jet
printer with low dpi: 16 shades of grey just doesn't make it. Color
is added to vary the apparent density but then the grays change their
tint when viewed by a different light and the eye is not well fooled
by the color dithering -- yellow + cyan + magenta = dark muddy brown.

As a further complication, an inkjet printer builds linear reflectance:
25% dots = 25% reflectance, 50% dots = 50% reflectance. The eye,
however perceives logarithmically ["God invented logarithms, man
invented the integers." - somebody famous] and the shades are not
equally spaced. If black is 2.0 OD:

printer #black dots/pix OD
9600 dpi/300 pix/inch printer 1024 2.00
1023 1.96
1 0.00042
0 0.00

1200 dpi/300 pix/inch printer 16 2.00
15 1.14
14 0.87
1 0.03
0 0.00

As is easy to see, there is no possibility for shadow detail in a 1200 dpi
printer.

If you use 8 bit software, though, you are often limited to 256 shades.

# black dots/pix OD Zone Shades/Zone change
255 2.0 0
254 1.86 I 1
251 1.59 II 3
245 1.31 III 6 - detailed black
232 1.00 IV 13 - dark grey
1 0.0017
0 0.00

Easy to see why so many digital photos have no shadow detail.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
To reply, remove spaces: n o lindan at ix . netcom . com
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