Hi Duncan,
I think we are basically talking about the same thing.
A lot of people confuse DPI with print quality.
You can have a 1200 DPI, 1200 DPI high quality, 600DPI and 600DPI Draft
settings.
The 1200 DPI high quality will be visibly darker, the 600 DPI draft will
be visibly lighter. A "standard" 1200DPI and "standard" 600 DPI setting
on the same printer should use slightly less toner on the 1200DPI setting.
I can do a print to file or a print to paper, the upside with a print to
file is I don't have to count the dots.
Grayscale is still the most common laser printer, color lasers are more
common then before, but no where near the level of grayscale.
I could do the images as black and white only, all that is going to do
is slightly increase the white pixel count, as some of the gray pixels
will fall to white instead of black, it won't really change it much.
My background with this is about 12 years ago, I implemented a print
quote system that actually took into account the coverage on the page to
charge the student accounts the "right" amount. Ie if some stupid
student decided that they liked reading white text on a black
background, they would get billed about about 20x as much as printing
black text on a white background. When you setup the environment you
tell the system the cost per toner cartridge, the rated coverage from
the MFG, the cost per sheet of paper, etc.
The software was called "printbill", the most recent update was in
2006... http://sourceforge.net/projects/pqadmin/files/printbill/4.2.1/
looks like the official website is gone, but this page has some info on
it: http://linuxappfinder.com/package/printbill and the archive.org
version of the official site:
https://web.archive.org/web/20090202073731/http://ieee.uow.edu.au/~daniel/software/printbill
-Harry
On 09/15/2014 03:10 PM, DSinc wrote:
Harry,
I will give you what you believe. No harm, no foul! I just don't get
your discourse. I only did 33 years supporting these beasties; and yes,
'Print Quality' was the primary service call. But still, I could be
wrong. Will not be the first time!
Yes, spurious toner isa problem. I don't speak to this. I assume the
developer housing seals are OK.Please let's not have a tomAtoes/tomahtoes
disucssion.
OK. Why 2 grayscale images? Grayscale seems to be some special
setting. What does 'grayscale' prove?
Why not print a 36 point (or even larger) 'A' at both 1200dpi and
600dpi? There should be a visible difference.
I'll assume you have an eye-loupe or a magnifying glass.
JMHO,
Duncan
On 09/15/2014 17:28, Harry McGregor wrote:
Hi,
So I went a step farther, I generated two grayscale images.
600x600 DPI, 1 inch
1200x1200 DPI, 1 inch
In each is a rendered letter "A", and it was saved as an LZW tiff, so
no lossy compression involved.
I only looked for "White" pixes, counting anything with any shading
in it as "using toner", which is a little overkill.
hmcgregor@hmcgregor-Satellite-L75D-A:~/Documents$ convert
600dpi_A.tif -format %c -depth 8 histogram:info:- | grep white
300762: (255,255,255,255) #FFFFFF white
hmcgregor@hmcgregor-Satellite-L75D-A:~/Documents$ convert
1200dpi_A.tif -format %c -depth 8 histogram:info:- | grep white
1205231: (255,255,255,255) #FFFFFF white
I took the white pixels in the 1200dpi and divide by 4 to get the
equivalent area coverage of 600:
1205231/4 = 301307.75000000000000000000
I subtracted the white pixels of the 600 DPI image from the white
pixels of the 1200 DPI image, and found:
301307.75-300762=545
So that means the 1200 DPI image has more "white" in it, but not by
much.
If you want to look at the grayscale aspects you can as well, but
overall, unless the printer is printing "lighter" at 600 DPI (ie
using the 1200DPI size pixels, and leaving space between pixels,
which printers tend to only do when in "Draft" mode), lowering the
DPI does not save toner.
This does not take into account "waste" toner, and some printers,
especially color lasers have more waste toner collection then
others. Most grayscale printers don't have waste toner collection,
and instead the waste is re-used within the toner cartridge.
-Harry
On 09/15/2014 01:44 PM, DSinc wrote:
Harry,
I am so glad you disagree'd. But, you miss the point. Itis not
'skipping dots'! It is how many dpi the printer does. The 'inch' is
a fixed number.
On my old BrandX printers we did 90K dots/sq in. This produced a
totally black square 1in.x1in.
The way the printer 'IT' is how the IG 'draws' IT. I accept your pix
of two resolutions, but I do not agree. Our 1 inch/square printed
'targets'
just got lighter; nothing more. There wasnohorizontal/vertical
difference. Thank you for your () add, but the other axis is quite
part of this
whole equation. All your pix shows me is 'character spacing.' That
is totally IG control. Has little to do with resolution.
HTH,
Duncan
On 09/15/2014 15:26, Harry McGregor wrote:
I don't agree that it has a direct relationship.
I really depends on how the printer deals with it.
If the printer does 600 vs 1200 DPI by "skipping" dots, then lower
DPI would save toner.
ie (linear only, not showing the other axis)
600 DPI "skipped"
X X X X X X
X X X X X X
X X X X X X
X X X X X X
X X X X X X
X X X X X X
Vs
600 DPI "Big"
XXXXXX
XXXXXX
XXXXXX
XXXXXX
1200 DPI may use a bit more or a bit less toner depending on the
way the printer renders it, but in most cases I would not expect a
significant change unless the printer was sill using 1200DPI dots,
and skipping pixels.
-Harry
On 09/15/2014 11:15 AM, Thane Sherrington wrote:
At 02:58 PM 15/09/2014, DSinc wrote:
Thane,
There is a complex formula and special page image that most
priter companies use to help them compute (fabricate/lie) about
their printed
pages/catridge. Please note that this business does NOT use 100%
coverage. I just do not know many folk that print fully black pages.
I have to claim age/time/forgetfulness for not recalling what the
'coverage' percentage was/is. But I do recall that there is a
specification
about this the all printer makers try to meet/exceed. And, alot
of this has do do with various makers 'image generators.'
Hi Duncan,
Yeah, I know about the page used (I've seen a copy from
Lexmark). I was just wondering if they are printing this page at
300dpi or 1200 dpi when they come up with the number of pages a
toner will print.
I was sitting down with graph paper trying to figure out
the dot coverage, so I appreciate your help. :)
T
