On 09/15/2014 04:58 PM, DSinc wrote:
Harry,
We continue to disagree minorly. I understand your position. I just do
not agree.
:)
But, FINE, inthe end we sorta get our prints at either 1200dpi or
600dpi. I still do not comprehend your use of 'Grayscale.' Sorry, I
just do not get this. If it works for you, fine. I just do not
comprehend r
what you are talking about. In my world, 'Grayscale' is a photographic
term ONLY. It is not part of a xerographic laser printer. Laser
printers (mostly) WRITE WHITE.
I rendered the image in 8 bit grayscale, but I only looked at pixels
that were white. I counted all other pixels as black. Technically I
should render it as 1 bit color (Black and white).
Here are the numbers with 1 bit color.
hmcgregor@hmcgregor-Satellite-L75D-A:~/Documents$ convert 1200dpi_A.tif
-format %c -depth 1 histogram:info:- | egrep '(white|black)'
232834: ( 0, 0, 0,255) #000000 black
1207166: (255,255,255,255) #FFFFFF white
1440000 Total pixes, which is 1200x1200
Taking the number of white pixels and dividing by 4 (since it takes 4 of
these pixels to equal the size of 1 600DPI pixel) = 301791.5
hmcgregor@hmcgregor-Satellite-L75D-A:~/Documents$ convert 600dpi_A.tif
-format %c -depth 1 histogram:info:- | egrep '(white|black)'
58449: ( 0, 0, 0,255) #000000 black
301551: (255,255,255,255) #FFFFFF white
360000 Total Pixels, which is 600x600
If we subtract the number of 600DPI white pixels from the number of
"same as 600DPI" 1200 DPI white pixels, we get 240.5 "extra" 600DPI
sized white pixels when printing with 1200 DPI then when printing with
600 DPI, which necessitates, that we saved 240.5 600DPI pixels worth of
toner, or 962 1200 DPI pixels worth of toner, by using 1200 DPI instead
of 600DPI to print the very large letter A.
The laser is turned off or delflected to leave a 'black dot' or
printable area. This latent image is what the
toner cartridge helps to deliver to the incoming page of paper. The
fuser fixes/melts the latent image to the paper fibers. The result is a
printed page. Yes it still seems like magic to me after all these
years! But, I see the magic each time I print a page.
It's a lot of very cool technology, but I think the way HP listed
resolutions with a print style together with the resolution, like
"600DPI Econo Mode" and "1200DPI HiRes" have warped the thinking on this.
As long as you don't change the intensity or amount of toner per pixel,
the 1200DPI is less toner, once you start messing with the intensity,
all bets are off. The reality is the amount less is so little, it
really does not matter.
If you can stand reading "econo mode" it saves toner, beyond that, don't
use "hi res" or other very high quality settings, and you won't use too
much extra.
-Harry
Best,
Duncan
On 09/15/2014 18:33, Harry McGregor wrote:
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
