Silver halide photo paper - what life

Hello,

I just ordered some prints from Kodak Express (Ofoto). Kodak uses
something called Digital silver halide printing. How is this different
from archival quality prints made from slides/negatives? And what life
can you expect from these prints?

Thanks,

Siddhartha

Dave wrote:
But (at least in the US), if you drop off a CF card or CD for
printing
at a mini lab they do it on the same RA-4 machine that they use to
make
prints from negatives (but not from slides - different process).
When I doubt, ask if they print using a wet/silver halide/RA-4
process
or not.

http://www.ofoto.com/PrintsOverview.jsp?

Kodak's Ofoto site says:
# We use digital silver halide printing to produce fine-quality
archival photographic prints.
# Because our prints are archival quality, they should last as long as
prints you would receive from a professional analog photo-processing
labratory.
# We use high-quality Kodak paper and state-of-the-art printers for all
Ofoto prints.

The Indian site (Kodak Express www.kodakexpress.co.in) doesn't say
anything about the process or paper but I believe it should be the
same.

Can someone point me to a link on how digital silver halide and
conventional printing work? Couldn't find much by googling.
Cheers,

Siddhartha

I'm sure that they're nice, long-lasting prints (I've used Ofoto
before), but I think calling them "archival" is stretching the
definition a bit.

Try searching for RA-4.

Dave

"Dave" writes:

The kiosk-style machines at mini-labs use something else (not sure if
it's dye-sub or what) that is inferior to silver halide.

It depends. Some kiosks are connected to dye-subs (typically Kodak in my
experience), while others connect to the machine in the back that is the same
machine that prints film (typically Fuji in the places I frequent).

But (at least in the US), if you drop off a CF card or CD for printing
at a mini lab they do it on the same RA-4 machine that they use to make
prints from negatives (but not from slides - different process).
When I doubt, ask if they print using a wet/silver halide/RA-4 process
or not.

Though depending on the training of the clerk, you might get the blank deer in
the headlights stare if you ask the question that way.

--
Michael Meissner
email:
http://www.the-meissners.org

True enough, sad to say.

George E. Cawthon wrote:
Are you talking about color? Silver halide is long term (100s of
years) if on archival paper, but that is black and white images. Add
color and you are talking about dyes, all of which fade. All colors,
no matter what its composition, with the exception of a few minerals,
fade over time. So don't expect ANY color print to last a normal
human lifetime.

Ok, so irrespective of digital or analog:
Silver halide process + B+W dyes = Archival quality
Silver halide process + Colour dyes = Fade because colour dyes fade
Thanks,

Siddhartha

Greetings Siddhartha,

The term in question likely relates to the use of a CRT Printer which
exposes digital images to traditional color (silver based) paper. This can
be done very fast and very efficiently. The rolls are then chemically
processed and prints provided. They will last for a very long time. A
simplified version of the chemical process is a process that includes the
release of dyes based on chemical reactions in the film that corresponds to
the silver that was exposed in a camera. When in contact with specific
chemicals, dyes are released as dye clouds and are obsorbed into the layers
of the emulsion based on . The silver is washed away leaving variations of
these dye clouds in various layers of the film to make up the image. It is
a similar process that occurs later if the film negative is printed.

The other process that was alluded to here was the Kodak Picturemaker at
which you can create a copy of a print, or print a digital image. This is
designed and intended for individual printing and so uses Dye Thermal
technology. It is equal in longevity to a silver based print. Dye
sublimation printing starts with a dye bearing film. This will either be a
single four layered film or four separate films. The primary colors for dyes
on the film are cyan, magenta, and yellow. Also, the fourth film contains a
semi-clear coating that is used to improve image stability and longevity.

During the printing process, the films are placed on the paper and heated up
by the print head. This will cause the dyes to leave the film and enter into
the paper where it cools and re-solidifies. This is the "sublimation" part.
Sublimation is when a solid changes directly to a gas, and than back to a
solid again. Because the dyes go from solid, to gas, and back to solid,
there is much less of a mess compared to liquid inks.

With Inkjet, there are two types of inkjet technology: continuous flow and
what is called 'drop-on-demand'. Continuous flow inkjet printing uses
electrostatic movements to select ink drops to form an image. Drop-on-demand
printing is either piezoelectric or thermal. Piezoelectric inkjet printing
uses a mechanical means to eject ink.

This technology uses heat to vaporize a very thin layer of ink that forces a
small drop through a tiny opening. This process is repeated very rapidly,
thousands of times per second. The hardware needed to bring all this to bear
is built right into the inkjet cartridge. No wonder these cartrdiges are
expensive. :-) Since the inks used are basically the same as any other
inkjet printing system, this has no significant, measurable effect on the
longevity of the print itself.

Kodak has introduced new Inkjet paper that when used correctly will yield
very long lasting prints. See the following URL for details.

http://www.kodak.com/go/inkjet

Talk to you soon,

Ron Baird
Eastman Kodak Company




"Siddhartha Jain" wrote in message
ups.com...
Hello,

I just ordered some prints from Kodak Express (Ofoto). Kodak uses
something called Digital silver halide printing. How is this different
from archival quality prints made from slides/negatives? And what life
can you expect from these prints?

Thanks,

Siddhartha

Ron Baird wrote:
Greetings Siddhartha,

The term in question likely relates to the use of a CRT Printer which
exposes digital images to traditional color (silver based) paper.
This can
be done very fast and very efficiently. The rolls are then
chemically
processed and prints provided. They will last for a very long time.
A
simplified version of the chemical process is a process that includes
the
release of dyes based on chemical reactions in the film that
corresponds to
the silver that was exposed in a camera. When in contact with
specific
chemicals, dyes are released as dye clouds and are obsorbed into the
layers
of the emulsion based on . The silver is washed away leaving
variations of
these dye clouds in various layers of the film to make up the image.
It is
a similar process that occurs later if the film negative is printed.

Thanks Ron. That was informative. And I received the prints from
KodakExpress. They've turned out to be really nice. I think I'll order
more from them

As a sidenote, I wrote to Kodak India asking for more info on the
printing technology they use (since there was no info on the site). All
the email from Kodak-India said was that they use Kodak paper and
chemistry. Maybe you can shoot a mail to your Indian counterparts to
put more info on the website or send more informative emails to
inquisitive customers

Thanks,

Siddhartha