Re: iPF5000 16 Bit Printing At Last?

Michael,

first, just as I learned that our eyes couldn't distinguish tonality
difference of less then 1% (on average) which mean having as high as 256 or
0.4% distinct tonal values printed should be more then enough to give the
appearance of continuous tonality gradation and an increase to 65000
distinct tones wouldn't change any of this

I wouldn't be surprised to find out that an 8 bit color printer is plenty
enough considering our eyes color discrimination capabilities. Epson claims
there printer can put as low as 4 pico liter of ink. Do you have an idea of
what this means, all I can say is you would need very precice lab equipment
to verify this. Now to be a true 48 bit color printer would require 16
million (2^24) times more color resolution capabalities then what is
currently available. If we bring this back to individual color or ink, this
mean only 256 times more precice control of the ink spray or 1/64 pico liter
Just in case you didn't know, that is

1
------------------- liter
64000000000000

Is this technically feasible? I'm sure it is, they can do much better then
that, think of the machine(s) used to "print" computer chips. I have a hard
time believing someone can build a true and precice 4 pl capable device for
much less then a $100. Just for moment, lets think of this, how can we
visualise how small a 4 pico liter droplet of ink is. From simple math and
for our purpose, let say our printer can print 300 dot per inch. Each dot
will have a diameter of 1/300 of an inch or 1/300 * 2.54 cm (0.0084667 cm).
We can figure the area of this dot or circle ( pi * d^2 / 4 ) and we know
the volume is given by area * heigth. I'll spare you from the details and
just say a barely visible 1/300 of an inch dot (0.003333 inch), would have
roughly 3/100000 of an inch of ink on it which makes it basically invisible
to our eyes. For those who don't have a clue about inches, all this mean a
dot of about 85 micron in diameter covered with 0.76 micron of ink. If we
say we can resolve on average 5 line pairs per milimeter each of those line
would have a 100 micron width and the contrast between those lines and the
background better be optimal for this to happen. Sandy told us the other day
that we could do better then that, he said the resolution can go up to 20
lines or 25 micron in width and this is fine with me if it's true of course
but even so I think all of you print many more dot per inch then 300, most
large format printer can do 2880 dpi, in that case this would bring the
tickness of a 4 pl drop to be about 6-7 micron this for a dot of 9 micron in
diameter. (This seems pretty close to the inverse of what is called the
"Golden Ratio")

I don't know how to say this politely but I think this should do, I think
printer makers do similar to what Macdonnalds does when they say there
hamberger is made of 100% pure beef.

To say: "allowing processing of 16-bit RGB images, which dramatically
increasing gradations and as a result, overall image quality." and assuming
you can see the kind of difference implied with this on a side by side
comparison is kind of an admission that the current printer are dramatically
over rated wouldn't you think? The numbers above, especially those about
resolution and those about tonal gradation basically say that the current
printer capabilities is well above what the eyes can discriminate. I'll
admit this about color, I don't know our eyes performance in that regard but
still if an 8 bit printer can put a dot of ink 2-3 times smaller then we can
resolve, assuming we can do 20 line pairs / mm and this dot is made of a 4
pl ink droplet which makes it highly improbable that such a small amount of
ink can result in a high enough contrast that we can even see this dot, of
course this is all base on what the printer makers claim there machine can
do. I would see no need for 16 bit printer but obviously if the 8 bit ones
we have now are not exactly what they seem (claim) to be that's another
story.

Regards
Yves

----- Original Message -----
From: "Michael Koch-Schulte" <mkochsch@shaw.ca>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Tuesday, May 09, 2006 8:25 PM
Subject: iPF5000 16 Bit Printing At Last?

> I just noticed this today, rather out of my budget at $2K but it's a start
> at 16-bit printing and can only get cheaper. Goodbye posterization for
good.
> ~m
>
> "Print Plug-in for Digital Photo Professional* (DPP) software allows users
> to directly process and print RAW image file from their DPP software. This
> plug-in is an export module that bypasses the operating-system-dependent
> print driver - allowing processing of 16-bit RGB images, which
dramatically
> increasing gradations and as a result, overall image quality.
>
Received on 05/10/06-10:18:51 AM Z