Can't believe someone would say this with a straight face
 

Alan Browne wrote:
On 2012.08.26 16:19 , R. Mark Clayton wrote:

The dot pitch of my printer is 1440 and the "standard" resolution is 360
dpi. At any normal viewing distance this is imperceptible.

Not when it dithers over blocks of 64 or more.

What do you mean? If I print at 360 on the Epson 3800 (head is 1440)
the dithering for a print dot should be no more than 4x4 (16 dithered
dots). [not counting dot 'edge' to dot 'edge' dithering]. Why would it
dither to 64 blocks?

So how many colour steps and gray steps do you get at 16 dithered
dots?

-Wolfgang

Can't believe someone would say this with a straight face
 

"Wolfgang Weisselberg" wrote in message
...
Alan Browne wrote:
On 2012.08.26 16:19 , R. Mark Clayton wrote:

The dot pitch of my printer is 1440 and the "standard" resolution is
360
dpi. At any normal viewing distance this is imperceptible.

Not when it dithers over blocks of 64 or more.

What do you mean? If I print at 360 on the Epson 3800 (head is 1440)
the dithering for a print dot should be no more than 4x4 (16 dithered
dots). [not counting dot 'edge' to dot 'edge' dithering]. Why would it
dither to 64 blocks?

So how many colour steps and gray steps do you get at 16 dithered
dots?

-Wolfgang

4 dots each magenta, cyan, yellow and black = 64k

You might manage a little more if some of the colours (like cyan and yellow
can print over each other, but obviously anything + black = black.

Can't believe someone would say this with a straight face
 

On 2012.08.31 08:51 , R. Mark Clayton wrote:
"Wolfgang Weisselberg" wrote in message
...
Alan Browne wrote:
On 2012.08.26 16:19 , R. Mark Clayton wrote:

The dot pitch of my printer is 1440 and the "standard" resolution is
360
dpi. At any normal viewing distance this is imperceptible.

Not when it dithers over blocks of 64 or more.

What do you mean? If I print at 360 on the Epson 3800 (head is 1440)
the dithering for a print dot should be no more than 4x4 (16 dithered
dots). [not counting dot 'edge' to dot 'edge' dithering]. Why would it
dither to 64 blocks?

So how many colour steps and gray steps do you get at 16 dithered
dots?

-Wolfgang

4 dots each magenta, cyan, yellow and black = 64k

You might manage a little more if some of the colours (like cyan and yellow
can print over each other, but obviously anything + black = black.

I get what you mean, however I doubt they can lay down all combinations
- there will be a lot of "holes" in the map that aren't used (useless
combinations or combinations that result in the same colour as another
combination - so it is not used (esp. "rich" black: black over colour).

Further, on the 3800, there are 8, not 4, colours available (increasing
the map considerably - minus the "useless" combos).


--
"C'mon boys, you're not laying pipe!".
-John Keating.

Can't believe someone would say this with a straight face
 

On Thu, 30 Aug 2012 23:32:18 +0200, Wolfgang Weisselberg
wrote:

Alan Browne wrote:
On 2012.08.26 16:19 , R. Mark Clayton wrote:

The dot pitch of my printer is 1440 and the "standard" resolution is 360
dpi. At any normal viewing distance this is imperceptible.

Not when it dithers over blocks of 64 or more.

What do you mean? If I print at 360 on the Epson 3800 (head is 1440)
the dithering for a print dot should be no more than 4x4 (16 dithered
dots). [not counting dot 'edge' to dot 'edge' dithering]. Why would it
dither to 64 blocks?

So how many colour steps and gray steps do you get at 16 dithered
dots?

I understand where you are coming from but the evidence is that the
Epson 3800 printer (at least) is not confined to the regular
deposition of drops in simple rectangular cells. See
http://gerryeskinstudio.com/ABW_sept.../image002-.jpg
Not only is it hard (?) to see any visible evidence a rectangular cell
containing dot patterns, but it is evident that there need be no
simple pattern of dot depositions.

Dots overlap each other in many places and the amount of overlap
varies from one position to the next. Drops are transluscent with the
result that overprinting causes colour-mixing and the formation of
colours other than those of the raw ink. And then there is the ability
of the printer to deposit drops of different sizes, although there is
little evidence of this in the particular example.

I don't know what the dithering algorithm is that is used by Epson but
I suggest it renders moot any analysis based on simple dot patterns
deposited in rectangular blocks or cells.

This started with comments by Mark Clayton about the printing of grey
scales (etc) by Mark Clayton. I suggest reading
http://gerryeskinstudio.com/ABW_sept08_paper/index.html
--

Regards,

Eric Stevens

Can't believe someone would say this with a straight face
 

Eric Stevens wrote:
On Thu, 30 Aug 2012 23:32:18 +0200, Wolfgang Weisselberg
Alan Browne wrote:
On 2012.08.26 16:19 , R. Mark Clayton wrote:

The dot pitch of my printer is 1440 and the "standard" resolution is 360
dpi. At any normal viewing distance this is imperceptible.

Not when it dithers over blocks of 64 or more.

What do you mean? If I print at 360 on the Epson 3800 (head is 1440)
the dithering for a print dot should be no more than 4x4 (16 dithered
dots). [not counting dot 'edge' to dot 'edge' dithering]. Why would it
dither to 64 blocks?

So how many colour steps and gray steps do you get at 16 dithered
dots?

I understand where you are coming from but the evidence is that the
Epson 3800 printer (at least) is not confined to the regular
deposition of drops in simple rectangular cells. See
http://gerryeskinstudio.com/ABW_sept.../image002-.jpg
Not only is it hard (?) to see any visible evidence a rectangular cell
containing dot patterns, but it is evident that there need be no
simple pattern of dot depositions.

All I see is that the head passes over the paper several times[1],
with different start timings (which explains the horizontal
overlaps) and I guess the head is slightly tilted (so e.g the
magenta rows are slightly shifted compared to the other rows).


Dots overlap each other in many places and the amount of overlap
varies from one position to the next. Drops are transluscent

matte ink, glossy paper
What happens?

with the
result that overprinting causes colour-mixing and the formation of
colours other than those of the raw ink. And then there is the ability
of the printer to deposit drops of different sizes, although there is
little evidence of this in the particular example.

I don't know what the dithering algorithm is that is used by Epson but
I suggest it renders moot any analysis based on simple dot patterns
deposited in rectangular blocks or cells.

Still, printer manufacturers give out dpi ...

Let's make a simple model:
Any spot on the paper can take only a given amount of ink
before it starts smearing and running. Any dot from the
printer has a minimum size and minimum amount of ink.

Thus: there's only so many dots that can be printed in any
given area on paper before there's too much ink. That gives
us a good idea of dpi.

-Wolfgang


[1] The ink nozzle firing repeat rate is too low to place dot
on dot in a single pass.

Can't believe someone would say this with a straight face
 

R. Mark Clayton wrote:
"Wolfgang Weisselberg" wrote in message
Alan Browne wrote:
On 2012.08.26 16:19 , R. Mark Clayton wrote:

So how many colour steps and gray steps do you get at 16 dithered
dots?

4 dots each magenta, cyan, yellow and black = 64k

ink limit.

So, how many magenta steps, green steps, and gray steps do
you get?

You might manage a little more if some of the colours (like cyan and yellow
can print over each other, but obviously anything + black = black.

Really? Anything + black = black? Try it yourself ...

-Wolfgang

Can't believe someone would say this with a straight face
 

On Tue, 4 Sep 2012 15:10:18 +0200, Wolfgang Weisselberg
wrote:

Eric Stevens wrote:
On Thu, 30 Aug 2012 23:32:18 +0200, Wolfgang Weisselberg
Alan Browne wrote:
On 2012.08.26 16:19 , R. Mark Clayton wrote:

The dot pitch of my printer is 1440 and the "standard" resolution is 360
dpi. At any normal viewing distance this is imperceptible.

Not when it dithers over blocks of 64 or more.

What do you mean? If I print at 360 on the Epson 3800 (head is 1440)
the dithering for a print dot should be no more than 4x4 (16 dithered
dots). [not counting dot 'edge' to dot 'edge' dithering]. Why would it
dither to 64 blocks?

So how many colour steps and gray steps do you get at 16 dithered
dots?

I understand where you are coming from but the evidence is that the
Epson 3800 printer (at least) is not confined to the regular
deposition of drops in simple rectangular cells. See
http://gerryeskinstudio.com/ABW_sept.../image002-.jpg
Not only is it hard (?) to see any visible evidence a rectangular cell
containing dot patterns, but it is evident that there need be no
simple pattern of dot depositions.

All I see is that the head passes over the paper several times[1],
with different start timings (which explains the horizontal
overlaps) and I guess the head is slightly tilted (so e.g the
magenta rows are slightly shifted compared to the other rows).

The diagnostic test procedure doesn't suggest the head is tilted. It's
more likely to be a subtle difference in timing of the droplet spray.


Dots overlap each other in many places and the amount of overlap
varies from one position to the next. Drops are transluscent

matte ink, glossy paper
What happens?

'Matte ink'? I'm not sure what you mean. The 3800 uses a pigment ink.

with the
result that overprinting causes colour-mixing and the formation of
colours other than those of the raw ink. And then there is the ability
of the printer to deposit drops of different sizes, although there is
little evidence of this in the particular example.

I don't know what the dithering algorithm is that is used by Epson but
I suggest it renders moot any analysis based on simple dot patterns
deposited in rectangular blocks or cells.

Still, printer manufacturers give out dpi ...

Buyers expect them, just as they expect megapixels in cameras.

'dpi' do make some sense. The 3800 has a basic pitch of 360/dpi which
can also manifest itself as 720/dpi. They also claim 1440/dpi and
2880/dpi. Some of the more recent Epson printers built around the same
mechanical print engine even claim 5760/dpi. Presumably these
subdivisions of the basic pitch are managed by software and timing in
some way. Once software comes into it there is no reason why dots
should be deposited in positions which are simple integer fractions of
the basic pitch.

Let's make a simple model:
Any spot on the paper can take only a given amount of ink
before it starts smearing and running. Any dot from the
printer has a minimum size and minimum amount of ink.

Thus: there's only so many dots that can be printed in any
given area on paper before there's too much ink. That gives
us a good idea of dpi.

There is nothing in the example I cited above which suggests that the
ink/paper is anywhere near saturation. The print-pattern is
predominantly white space.

-Wolfgang


[1] The ink nozzle firing repeat rate is too low to place dot
on dot in a single pass.

Agreed, but we are talking about the print pattern, and the number of
colours it can generate. I don't think we are really much concerned
about how the print pattern is generated.
--

Regards,

Eric Stevens

Can't believe someone would say this with a straight face
 

On 2012-09-04 15:06:14 -0700, Eric Stevens said:

On Tue, 4 Sep 2012 15:10:18 +0200, Wolfgang Weisselberg
wrote:

Le Snip


matte ink, glossy paper
What happens?

'Matte ink'? I'm not sure what you mean. The 3800 uses a pigment ink.

The R2880 uses 9 "Ultra Chrome" inks, but only has slots for 8. So when
printing on matte paper or non gloss B&W you exchange the "Photo Black"
cartridge with the "Matte Black" cartridge. This is a royal PITA!

In my hand I am holding the three #96 black cartridges intended for use
in the R2880; "Light Black", "Light Light Black", "Photo Black", &
"Matte Black".


--
Regards,

Savageduck

Can't believe someone would say this with a straight face
 

On 2012-09-04 16:28:21 -0700, Savageduck said:

On 2012-09-04 15:06:14 -0700, Eric Stevens said:

On Tue, 4 Sep 2012 15:10:18 +0200, Wolfgang Weisselberg
wrote:

Le Snip


matte ink, glossy paper
What happens?

'Matte ink'? I'm not sure what you mean. The 3800 uses a pigment ink.

The R2880 uses 9 "Ultra Chrome" inks, but only has slots for 8. So when
printing on matte paper or non gloss B&W you exchange the "Photo Black"
cartridge with the "Matte Black" cartridge. This is a royal PITA!

In my hand I am holding the three #96 black cartridges intended for use
in the R2880; "Light Black", "Light Light Black", "Photo Black", &
"Matte Black".

This is getting like a Monty Python routine. Not three black
cartridges, four, but only three of the blacks are in the printer at
any time.

--
Regards,

Savageduck

Can't believe someone would say this with a straight face
 

On Tue, 4 Sep 2012 16:28:21 -0700, Savageduck
wrote:

On 2012-09-04 15:06:14 -0700, Eric Stevens said:

On Tue, 4 Sep 2012 15:10:18 +0200, Wolfgang Weisselberg
wrote:

Le Snip


matte ink, glossy paper
What happens?

'Matte ink'? I'm not sure what you mean. The 3800 uses a pigment ink.

The R2880 uses 9 "Ultra Chrome" inks, ...

which inks are 'pigment inks'. See
http://www.epson.com/cgi-bin/Store/L...raChromeK3.jsp

... but only has slots for 8. So when
printing on matte paper or non gloss B&W you exchange the "Photo Black"
cartridge with the "Matte Black" cartridge. This is a royal PITA!

In my hand I am holding the three #96 black cartridges intended for use
in the R2880; "Light Black", "Light Light Black", "Photo Black", &
"Matte Black".
--

Regards,

Eric Stevens