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A digital printer is a
printer that is specifically made to print photographs from digital
cameras. Look for the term
"photo-realistic" or "photo-quality" when you shop for a color
printer. You want a digital printer that can deliver photo-realistic
results so your images will look as close to real photographic
prints as possible. It
isn't always the most expensive digital printer that gives the best
results. Near
photo-quality printers are available for less than $100.
How Color Images are Printed...
Most digital printers use a combination of
three, four, or six colors to print full-color images. All printers
use cyan, magenta, and yellow - the three primary colors used in
printing - as their base colors.
Color printers create images by
dividing a page into thousands, or even millions, of tiny dots, each
of which can be addressed by the computer. As the printer moves
across and down the page, it can print a dot of color, print two or
three colors on top of each other, or leave the spot blank (white).
To get the countless variations of colors in
a photograph, the printer generates a pattern of small dots that the
eye blends to form the desired shade. This process is called
halftoning or dithering. Printers vary widely in the halftone
methods used and the results obtained. One sign of halftoning done
well is when a smooth gradation of color in the print. If the
process isn't well done, transitions will be made up of bands of
color and may include a moiré pattern. You can see the halftoning in
a magazine photo by looking at it through a magnifying glass.
Factors to consider...
Printer Resolution (dpi) -
Although digital cameras use pixels to measure image resolution,
printer resolution is based on the number of dots per inch (dpi) the
printer lays down on paper. The higher the dpi, the smaller the dot,
and the better your picture. A printer that delivers 600 dpi
resolution is usually considered photo-quality.
Ink Application - The way the
ink is applied also affects the quality of the product. An ink-jet
printer with a resolution of 1400 dpi won't give as good a print as
a dye-sub printer at 300 dpi. This is because, each pixel on an
ink-jet printer isn't a single drop of color but a cluster of many
drops. The accuracy with which this is done can have a great impact
on the final resolution of the print.
Ink Cartridges - If you
purchase an inkjet printer, try to get one that uses a separate ink
cartridge for each color. If you’re printing a lot of pictures with
one color in them, this multi-cartridge approach will let you
replace just the color that runs out. You'll also want to compare
prices of the different brands of ink
cartridges. An inexpensive printer might not be such a good deal if
it uses expensive in cartridges.
Ultraviolet Coating - In
addition to improvements in ink quality, some printer manufacturers
have added a UV coating to the print production process to protect
your prints from UV damage. The UV layer may add decades to a
print's life expectancy.
Photo Paper - Paper is a very
important component to the quality of a digital print.
You should price the photo
paper before making your printer decision. Many printer makers offer
their own brand of photo paper, which is optimized with their ink.
This coating contains the ink that is sprayed on it limiting color
bleed. You won't get a
good print from a porous paper that is not designed for printing
photo-quality images.
Data Card Slot - Another option
to check is to see if the printer has a slot for the data card from
your digital camera. This can be a handy way of printing photos
quickly and directly without connecting to a computer.
Dare to Compare - Be sure to
run a test print (or two) before you buy any photo printer. For a
true comparison, you should run the same exact print on all printers
you are considering. On an 8x10-inch print, there should be no
visible dots, dithering, banding, or jagged edges from a distance of
8 inches. Also check how long it takes to print an image. The
printer's specification sheet will tell you the average print speed
in prints-per-minute.
Digital Printer
Options...
Each type of digital color printer
approaches the task of depositing ink or dye on paper using a
different method. Here
are four options to consider...
Liquid Ink-jet printers
use ink-jet cartridges that propel fine droplets of liquid ink
toward the surface of paper. A cartridge of ink is attached to a
print head with up to hundreds of nozzles, each thinner than a human
hair. The number of nozzles and the size of each determines the
printer’s resolution. As the print head moves across the paper, a
digital signal from the computer tells each nozzle when to propel a
drop of ink onto the paper. Each pixel in the image can be made up
of a number of tiny drops of ink. The smaller the droplets, and the
more of them, the richer and deeper the colors should be. For
ink-jet printers, the size of the ink drops is more important that
the dpi. While you can print photos on plain-paper, liquid inks
tend to soak into the paper and blur.
You'll get better results with coated papers that are designed
specifically for your printer.
If you’re in the market
for an affordable color printer, you should consider an inkjet
printer.
Dye-sublimation printers are high quality printers.
Dye-sublimation printers produce photo-realistic continuous-tone
images that look like they came from a photo lab. Dye sub printers
have their colored dyes in a transfer roll or ribbon that contains
consecutive page-sized panels of cyan, magenta, yellow and black
dye. These printers require special paper that's designed to absorb
the vaporous dye on contact. Cost per page is high, $3 to $4 dollars
for a letter sized page. During printing, separate passes are made
across the print for each of the four colors. A thermal print head,
consisting of thousands of heating elements, contacts the media
being printed on and vaporizes the solid dyes. The resulting gas
diffuses into the surface of the paper. Because the dyes are
transparent, a cyan dot may be printed on top of a magenta dot to
make a blue dot. By varying the amount of C, Y, and M, any color
within the printer's color gamut may be produced. Because they can
vary the density of each color, dye-sub printers are the only ones
that don't have to use halftoning or dithering to create a wide
range of colors. And because there are no dithered dot patterns, the
colors are applied in a continuous tone; producing photo-realistic
images.
Solid Ink-jet printers produce high-quality images with
sharp edges and good color reproduction. They are great for
producing reports and publications with color graphs or other
graphics on ordinary paper. They are also produce high-quality
transparencies at low cost. Color sticks in Cyan, Magenta, Yellow,
and Black are installed in the printer. Solid ink printers can print
on nearly any kind of paper stock. Solid ink-jet printers use solid
ink sticks that are melted into a reservoir and sprayed through tiny
nozzles onto the page where it immediately hardens. In the final
step, the paper moves between two rollers to cold-fuse the image.
Color Laser printers are high in cost and their quality
has not yet matched the very inexpensive ink-jet printers. The toner
is fairly durable and less sensitive to fading from exposure to
light than some other technologies. The colors for laser printing
are contained in four separate toner cartridges, one each for cyan,
magenta, yellow and black. No special paper is required. Laser
printers use a technology similar to that used in copiers. A laser
beam is focused on a photoelectric belt or drum, creating an
electrical charge in areas where toner is to adhere. Charged toner
is then attracted to those places on the belt or drum. Electrostatic
charges cause the toners to adhere to the belt. With black and white
printers, this process happens once but with color printers it is
repeated for the cyan, magenta, yellow and black components of the
image. The image, composed of the four toner colors, is then
transferred to a drum which rolls the toners onto the sheet of paper
or transparency. The toners on the paper are then fused using either
heat or a combination of heat and pressure. |