A
Additive Color: Commonly called the RGB color model. A color model where all
the colors are created by combining the primary colors - red,
green and blue together in different combinations, hence the
acronym RGB. White is produced when the primaries are added
together equally in their strongest form. Light-based systems,
such as computer monitors, employ this type of color. The
color gamut, or color range, of RGB systems is generally very
broad. See also Subtractive Color.
Adobe RGB 1998: A version of the RGB color model with an expanded color space
developed by Adobe Systems. The model provided an answer to
the rising demand for color integrity, color management and
color profiling not met by the minimal color space standard
defined by sRGB.
Alias: The stair-stepped pattern of odd angles on edges of a bitmapped
image whose resolution is too low. Also known as "jaggies."
See also Anti-Aliasing.
Anti-Aliasing: The smoothing out of the stair-stepped pattern, or jaggies.
This is done by increasing the resolution, or pixel count,
of a bitmapped image and averaging the color steps between
edge boundaries.
Archival Inks: A newer ink base that uses pigments designed to maximize the
length of time before colors begin to fade.
Archiving: Digital images, along with information on how to replicate
a print according to the Bon-A-Tirer, or artist's proof, that
the artist has signed off on, are stored on some sort of permanent
media such as a CD-Rom. This is for the purpose of creating
new runs of that print without extensive setup time.
Artifact: Visible image destruction introduced by various means, such
as employing some sort of lossy type of compression like JPG,
electrical noise from a camera, or any of a number of physical
deficiencies that can mare an image
Artist Proof: A test set of prints, produced at the start of a run of a
numbered print edition, but outside of the numbered series,
used to calibrate and stabilize the colors in the edition.
Also called "Aps." Artist's proofs usually sell
for more than the serialized prints from an edition. See also
Bon-A-Tirer.
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B
BiCubic Resampling:
A method of increasing an image pixel count by moving pixels
an "x" distance, sampling the colors of its neighbors
and creating new pixels based on an average of those colors.
It is a reasonable method of interpolating an image's pixels,
but, on larger scales, yields a soft image.
Bitmap:
An image made up of a mosaic, or tiles, of color information,
as opposed to an image made up of vector information (an object
oriented image).
Bon-A-Tirer (pronounced bone-ah-ti-ray):
The proof which is signed off on by the artist as the approved
benchmark from which all subsequent prints in that series
are judged for quality. The Bon-A-Tirer, or BAT, is archived
in a dark place to prevent color shifting and is used in comparing
color quality in later printings of that series.
Bruce RGB:
A version of the RGB color model with an expanded color space
developed by Bruce Frasier, a well-known color consultant,
in answer to the rising demand for color integrity, color
management and color profiling not met by the smaller color
space standard defined by sRGB.
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C
Calibration:
The act of bringing devices such as a monitor, scanner or
printer within specified tolerances in order to maintain consistent
and predictable color throughout the printmaking workflow.
CCD (Charged Coupled Device):
A light sensor that is employed by scanners and digital cameras
to convert analog data into digital data. CCD's can be arranged
in various configurations:
Single rows - a bar with a single line of sensors on it. With three
bars - one to capture each of the RGB's separate components
as the bars are passed over the material being captured. Or
they can be arranged in an array, to capture a rectangular
field, the way film does from a 35 mm camera. See also Scanner,
CMOS.
Chroma:
The strength or weakness of a chromatic color, such as a "weak
color," a "strong color," or an "intense
color." See also Saturation.
Chromatic Colors:
Iincludes all color that contains both hue and chroma, with
the exception of neutral colors.
CIE (Commission Internationale de l'Eclairage):
The international organization that developed a set of color
definition standards endorsed by Adobe Systems.
CIE-Lab Model (Luminance, a and b):
This is the universal, theoretical color space in which all
other color spaces are contained. It describes color in three
dimensions, on x, y and z axes, with luminance, or lightness,
being the z (vertical) axis, from totally dark at the bottom
to totally bright at the top. The other x and y axes (a and
b) define a location on which any color possible can be called
out. The a axis represents color transitions between red and
green, the b axis represents color transitions between blue
and yellow.
CMOS (Complimentary Metal Oxide System):
An emerging light sensor technology offered as an alternative
to CCD (Charged Coupled Device). CMOS offers more dense light
sensors per square centimeter than CCD and has a broader dynamic
light range than CCD, thus it will yield more shadow detail
and more highlight detail with less color distortion from
uncontrolled light sources. As the technology matures, CMOS
will eventually be less expensive to produce than CCD. See
also CCD.
CMYK Color Model (Cyan, Magenta, Yellow and Black):
The subtractive color model used in traditional web presses
and inkjet printers. It has a limited gamut compared to RGB,
but can create the most color variety for the fewest inks
employed.
Coatings:
After printing, a clear coating is applied to a print to protect
it from smudging or smearing from water or fingerprints. Coatings
usually do not increase the fade resistance of a print, however.
Coating a canvas will make it waterproof so that it does not
have to be mounted under glass or Plexiglas.
Cold Press Paper:
Watercolor paper is made uniformly flat by passing it through
a press during the drying process. The press can be either
heated or remain cold. Cold press paper has a coarser and
rougher finish and is more absorbent than hot press paper.
It will absorb more ink and diffuse the color more than hot
press paper, and tends not to have the crispness or brilliance
of hot press papers. Instead, it imparts a more mellow feel
to the print, yielding less detail. See also Hot Press Paper.
Collaborative Printmaking:
The process of an artist working closely with a printmaker
to produce an original print, especially an original digital
print or one requiring considerable alteration to the original
image.
Color Correction:
The process of normalizing, changing or enhancing the colors
in a digital image to achieve the effect, either of realism
or of an artificial effect, which the artist or printmaker
wishes to achieve from the final print.
Color Management System:
A technology that creates color profiles of the devices in
the workflow - the monitors involved, the capture devices
and the printer to the specific inks and papers - so that
color accuracy can be maintained throughout the printmaking
process.
Color Model:
A scientific set of rules and definitions used to give a consistent
language to people who need to define and describe color when
communicating with one another. Examples of some color models
are: RGB, HSB, CIE-Lab, CMYK.
Color Profile:
See Profile, ICC Profile
Color Space:
Each color model has a different size or range of colors,
which is described as its color space. The RGB color space
is much larger than the color space of the CMYK model. The
Adobe 1998 color space is a larger space (contains more colors)
then the sRGB color space, although both the Adobe RGB and
sRGB are included in the RGB color model.
ColorSync:
On a Macintosh computer, a set of extensions to the operating
system that provide a basic Color Management System (CMS)
and a foundation for other CMSs to build upon. See also Profile.
Contrast:
The relationship between the lightest and the darkest areas
of an image. An image with deep shadows, bright highlights
and few steps between the two is said to be high contrast.
An image with weak shadows, dim highlights and many smooth
steps between the two is said to be low contrast.
Compression:
The black art of reducing the amount of space needed to store
a digital image onto a digital media such as a hard disc or
CD-Rom. Compression can be broken into two types: lossless,
in which the true integrity of the image is maintained, and
lossy, in which the original image is altered on compression
and data is thrown away, sacrificing image quality for a high
compression ratio.
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D
Deckled Edges:
When the craft of watercolor paper-making began, the papers
were made in single sheets, the pulp being laid out on a screen
to dry. The edges were naturally formed - not being cut, they
had a soft fractal boundary which became known as a deckled
edge. This became a desirable attribute to the aesthetic of
displaying watercolors, demonstrating the high quality of
the paper. As watercolor paper making technology progressed
into making it by the roll, the outer edges were left to deckle.
Paper from a roll will have two deckled edges and two cut
edges. "Torn Deckles," a simulated deckle, can be
created by wetting the edges, gently tearing the paper, then
using a flat piece of plastic or bone to smooth the paper
out. Papers with deckled edges should ideally be mounted with
the deckles showing, not hidden behind a mat.
Desaturate:
Reducing the saturation of a chromatic color by adding gray
to it.
Digital Fine Art Print:
Any fine art print made with a digital process and printed
on a digital printer.
DPI (Dots Per Inch):
This is the number of dots per linear inch that a specific
printing device lays down onto the media. People often confuse
DPI with PPI (pixels per inch) with disastrous results when
they print out their files. See also PPI.
Dye Based Ink:
Ink that consists of dyes as the means of transmitting color.
Dyes have a lighter consistency carrier and transmit color
to the media by staining the media. While tending to be thinner
in consistency, dyes have very bright and highly saturated
colors. Dyes, however, are not as permanent as pigments, tending
to fade more quickly in visible light. See also Pigment Based
Ink.
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E
EPSF (Encapsulated Postscript File Format):
A text based file format developed by Adobe Systems which
includes two images: A Postscript version, which is a resolution
independent text description of what a page looks like, and
a low-resolution bitmapped picture of that page used to preview
the high-resolution description from some other place, such
as a page layout program. See also Postscript.
F
File Format:
A defined method of packaging digital information, such as
a digital image or a text document, for storage. Formats are
attained on saving a file and are lost when a file is opened.
They are designed to preserve different aspects of the information
according to the needs of the person creating that file, such
as being able to open the file on a different operating system,
being able to maintain color profiles and other meta data,
being able to employ an optimal compression scheme, etc. Examples
of file formats are: TIF, EPS, STN, PSD, PDF.
Fractal Scaling:
A patented algorithm that uses fractal geometrical math to
scale a bitmapped digital image by analyzing the fractal geometry
within the image, thus maintaining the quality and integrity
of that image to a higher scaling factor than any other method.
See also BiCubic Scaling, STN.
FTP (File Transfer Protocol):
A protocol designed to allow two devices to transfer files
between them on the Internet. Various client software is written
to this standard for distribution.
Future Ink Test Print:
A print created with newly released inks to test and compare
the colors to an older ink set and approve the new inks with
the artist.
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G
Gamma:
The measure of how compressed or expanded the dark and light
shades become in an image.
Gamut:
The range or limits of a color space that a device, such as
a monitor or a printer, can express.
Giclée (Pronounced ghee - klay):
French meaning "spray" or "to spray."
A common term for fine art digital prints made from an inkjet
printer.
Grayscale:
The full range of neutral colors. A computer can express black,
white and 254 levels of gray between the two extremes.
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H
Hot Press Paper:
Watercolor paper is made uniformly flat by passing it through
a press during the drying process. The press can be either
heated or remain cold. Hot press paper has a tighter and smoother
finish and is less absorbent than cold press paper. It will
maintain a crisper, brighter look than cold press paper. Also,
you can distinguish more detail when printing to hot press
paper. See also Cold Press Paper.
House Papers:
The fine art papers that are in the normal inventory of a
specific printmaker.
HSB Color Model (Hue, Saturation and Brightness):
A color model in which color is described as hue, saturation
and brightness. Hue is a specific chromatic color, represented
by an angle called out on an arc from 0 to 360 degrees of
a color wheel. Saturation describes how intense that hue is.
And brightness refers to the variation from light to dark,
with a high brightness being lighter. People more naturally
think in the HSB color model than the RGB color model, thus
it is included in many image editing applications. See also
Color Model, HSV, RGB.
HSV Color Model (Hue, Saturation and Value):
A color model in which color is described as hue, saturation
and value. Hue is a specific chromatic color, represented
by an angle called out on an arc from 0 to 360 degrees of
a color wheel. Saturation describes how intense that hue is.
And value refers to the variation from light to dark, with
a low value being darker. Very similar to the HSB color model,
but with an emphasis on value as a measure of darkness. See
also Color Model, HSB, RGB.
Hue:
The distinctive characteristic of any chromatic color. Color,
described in terms of hue, is red, blue, purple, etc.
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I
ICC, International Color Consortium:
A consortium of companies with interests in color management,
working on a standardized specification for color management
technologies. ColorSync 2.0 is an implementation of the ICC
specification.
ICC Profile:
A standardized color profile conforming to the ICC specification
to ensure transportability between differing platforms and
devices. See also ICC, Profile.
Interpolation:
The use of an algorithm to create new pixels or eliminate
pixels in an image as it's sized up or down, with the intent
of maintaining the quality of detail that exists in the original
source image. With the exception of fractal scaling, most
interpolation is limited to very small scales.
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J
Jaggies:
Slang for an aliasing effect. See also Alias, Anti-Alias.
JPG or JPEG File Format (Joint Photographers Expert Group):
An older file format, derived by a subset of the ISO (International
Standards Organization) called the Joint Photographers Expert
Group, for the compression, storage and transmission of digital
images. It employs a method called Discreet Cosine Transform
that reduces the colors in an image, thus making an image
less complex. First used by field photographers transmitting
images over satellite feeds for the Associated Press, later
adopted as an ad hoc standard for displaying full color images
on web pages efficiently, this format is a lossy form of compression
which severely alters images and introduces "JPG artifacts"
every time a file is saved into it. It is not a recommended
format for saving high quality images.
JPG2000 or JPEG2000:
An initiative by the Joint Photographers Experts Group to
update the aging JPEG standard to meet the demands of image
compression in the 21st century. At this writing, it hasn't
been fully deployed. It employs a lossless wavelet form of
compression that preserves the integrity of an image when
saved.
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L
LPI (Lines Per Inch):
When a continuous tone image needs to be translated into dots
of varying sizes so that it can be separated to make a plate
for a web press, it is filtered through a screen, either physically
or by computer. The density of the screening process is measured
in lines per inch
Luminosity:
A value corresponding to the brightness of a color. A yellow
street sign photographed at dusk would have low luminance,
or luminosity. That same sign, photographed at 2 p.m. on a
sunny day, would have high luminosity. If a cloud comes by
and covers that bright sun, the yellow in the sign would exhibit
medium luminance.
LZW Compression (Limpel-Zev, Welch):
A form of compression invented by the individuals whose name
it bears for the compression of text transmission over telephone
lines, and later adopted in the compression of image data
in the TIFF format. This form of compression is a lossless
compression form, known as a zero tree entropy form, with
ratios varying depending on the color complexity of an image.
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M - N - O
Media:
The actual material that is to be printed on, such as watercolor
paper, glossy photo paper or canvas.
MegaPixel:
This is an approximate measure of an image's resolution. One
MegaPixel equals approximately one million pixels. It is only
approximate because it is a term derived by the marketing
departments of camera manufacturers, not engineers, and different
formulas are used to determine what a MegaPixel is, including
varying the definition of one million pixels. Some argue that
a MegaPixel is one million pixels. Some argue that it is 1,024,000
pixels. It was derived to help digital camera buyers more
readily understand the resolution of a camera. A more accurate
measure of an image's resolution is its pixel count.
Neutral Colors:
Colors that lack both hue and chroma, which include black,
white and the levels of gray in between. Also called achromatic
colors. See also Grayscale.
Original Digital Print:
Original artwork which employs a digital process in its creation.
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P
Pigment Based Ink:
Ink which consists of pigments as the means of transmitting
color. Pigments consist of a colored substance, usually from
a natural, organic source, suspended in a carrier, which coats
the media instead of dyeing it. Because of this type of deployment,
pigmented inks lack the color brilliance of a dye based ink
but have a greater resistance to fading. Pigment based inks
are the best for long-term archival purposes. See also Dye
Based Ink.
Pixel:
Short for Pixel Element - the basic element or fundamental
building block of a bitmapped image. It is a colored tile
which, when displayed in a mosaic of thousands or millions
of other pixels, comprises a digital image.
Pixel Count:
The number of pixels in an image, derived by multiplying the
pixel width by the pixel height. The resulting number represents
the true resolution of an image. Marketing materials state
this number in MegaPixels, with one MegaPixel equaling approximately
one million pixels. See also MegaPixel.
Pixel Height:
The number of linear pixels an image is high. This, multiplied
by the pixel width, is the true resolution of an image.
Pixel Width:
The number of linear pixels an image is wide. This, multiplied
by the pixel height, is the true resolution of an image.
Photo CD:
A proprietary file format created by Kodak. It employs an
integrated system of scanning imagery through supplied hardware
into Multiresolution Image Packs (MIP) and stores these MIP's
onto a CD-Rom using a closely guarded, proprietary compression
scheme. This allows the user to open images at different sizes
and resolutions. There is a Pro version that yields reasonably
high-resolution images.
Piezo/Micropiezo:
A printer head technology that uses micro-electric firing
of crystals to control the flow of ink to the substrate. Micropiezo
is a smaller version, or unit of measurement, than a piezo.
POD (Print On Demand):
With the storage of the digital print file and all of the
related information used to replicate a print series, art
can be printed in small runs, as needed, on demand.
Postscript:
A language that is a text based description of a page, developed
by Adobe Systems. It is the native language of almost all
high-resolution output devices used for prepress work employing
objects and text, such as an imagesetter.
Print File:
The actual computer file that created the Bon-A-Tirer, or
BAT, which is then used for the print series and archived
for future use.
Printmaker:
The individual who actually makes the prints.
Profile:
In a color management system, a file containing data representing
the color reproduction characteristics of a device, producing
what are known as printer profiles, monitor profiles, scanner
profiles, or in general, device profiles. A profile is created
by using calibration or characterization methodology, or a
combination of the two.
PPI (Pixels Per Inch):
The number of pixels you decide to fit onto a horizontally
linear inch of an image. This is an entirely arbitrary number.
You can fit as few or as many pixels onto an inch as you desire.
The result will be a change in the physical print dimensions
of the image and in perceived resolution of the image. For
example, an image that is 1000 pixels by 500 pixels will print
out at 3.3" x 1.6" at 300 ppi. It will also print
out at 6.6" x 3.3" at 150 ppi. At 72 ppi, that image
will print out at 13.8" x 6.9". Although the size
of the printed image and perceived resolution of the image
will vary, it is exactly the same image and has the same resolution.
PPI is often confused with DPI (dots per inch). See also Pixel,
Pixel Height and Pixel Width, Resolution, MegaPixel and DPI.
Proof:
A smaller print, printed at 1/2 to 1/3 size or on an "A"
size sheet, used to evaluate the quality of the print before
an edition is begun.
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R
Reflective Media:
Media that reflects light, such as a photograph, watercolor
or other opaque media. Colors reflected off media are not
as intense or as bright as those that are transmitted through
the media
Resampling:
See Interpolation.
Resize:
See Interpolation, Scaling.
Resolution:
The amount of detail that can be resolved out of the image.
The higher the pixel count, the greater the resolution, or
more detail can be resolved. A 4" x 5" image with
1 ppi has no resolution (no detail can be seen in the image).
Whereas, in a 4" x 5" image with 300 ppi, a lot
of detail can be seen, so it has high-resolution. And in a
4" x 5" image with 72 ppi, only a moderate amount
of detail can be seen, so it has low-resolution.
RGB Color Space (Red, Green, Blue):
The additive color model used in digital images and displayed
on a monitor, or CRT. An image consists of a composite image
made by blending three color layers together. One layer contains
the red information of the image. One contains the green information.
And the third layer contains the blue information. This color
model has a very broad and bright color gamut. Skill and experience
must be used in translating the strong, bright colors into
the more limited subtractive color spaces of models such as
CMYK to maintain the integrity of an image as it is printed.
RIP (Raster Image Processor):
A device that rasterizes (turns into pixels) vector data,
such as the text description of a page fed to the RIP by Postscript.
RIPs have a chip that speeds up the rendering of images to
a printer and, theoretically, handles color management information
more accurately.
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S
Saturation:
A measure of the purity of a chromatic color. A pure chromatic
color without white, black, or gray in it is said to be highly
saturated. A chromatic color that has been diluted with white,
black or gray is less saturated. A color with little chromatic
color and a large amount of white, black or gray is said to
be desaturated. See also HSB.
Scaling:
See Interpolation
Scan:
(n.) - the actual digital file containing an image that has
been digitized by a scanner is called a scan. (v.) - to scan;
the act of creating a source digital image (a scan) by capturing
an analog image into digital medium by use of a scanning device.
Scanner:
The device that captures a physical object or image (an analog
image) and converts it into the digital medium. Scanner types
include: transparency; flat bed; and drum, which uses a rotating
drum to scan the image. Scanners also include types that scan
in three dimensions, such as digital video and still cameras.
A video camera uses a CCD to scan many low-resolution images
in. A digital camera scans with a CCD or a CMOS to digitize
a single, moderate resolution image. There are table- mounted
cameras that scan in a high-resolution 3-D image, such as
the rare "Panoscan," of which there are only 40.
It scans a single row CCD of an area and digitizes a 300 Megabyte
image from 3-D space. There are still others that are stand-mounted.
Artwork is placed on a wall and the camera scans an image
in at around 4000 pixels square. Yet another uses three CMOS
chips (one for each RGB color) to capture a 48 Megabyte image
from 3-D space, which must be static
Shade:
Reducing the saturation of a chromatic color by adding black
to it.
sRGB:
The lowest common denominator for the RGB model. It is the
smallest color space defined by the RGB color model, thus
guaranteeing accurate color data between unpredictable devices.
It is used when someone wants to develop a format and guarantee
that the file can be recognized by any other system, without
predicting what the characteristics of that foreign system
are, such as setting a minimum standard by the ISO. It is
not a recommended color space for high quality color work,
as it is a clipped version of the larger color space in the
RGB color model - use Adobe RGB or Bruce RGB instead.
STN (STiNG File Format):
A proprietary file format patented by Iterated Systems, developed
into a Photoshop plug-in by Altamira Group and distributed
by LizardTech as the Genuine Fractals Photoshop plug-in. It
employs a lossless wavelet based compression scheme and a
fractal based algorithm for scaling an image to a very high
and accurate degree while maintaining the resolution in the
source image. Over the years it has become the ad hoc standard
for scaling, archiving and sometimes transporting high-resolution
digital imagery, especially photography.
Substrate:
The actual material that the digital printer lays ink onto,
such as the sheet of paper, canvas, film or whatever else
is properly prepared and run through the printer.
Subtractive Color:
Commonly called the CMYK color model. White is produced when
subtracting the primaries Ñ red, yellow and blue. Cyan,
magenta and yellow pigments or dyes are used in printing presses
to approximate these primaries, and black is added to compensate
for chemical impurities, creating richer blacks and deeper
shadow tones. In newer inkjet printers Cyan Light and Yellow
Light are also added to add color to the highlights less than
20%. The color gamut of CMYK systems is generally very narrow
compared to RGB. See also Additive Color.
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T - Z
TIF or TIFF File Format (Tagged Image File Format):
A proprietary file format developed by Aldus Systems, later
bought by Adobe Systems. It was developed to transport and
open bitmapped images across different platforms while maintaining
the quality and integrity of the image. It is highly extensible
and can employ several different compression schemes such
as LZW, JPG, CCITT or no compression, and its byte order can
be shuffled on Save to accommodate different platforms. Because
of this flexibility, it has been licensed and deployed by
many imaging applications and has become an ad hoc standard
for storing lossless bitmapped information when it comes to
high-resolution images.
Tint:
Reducing the saturation of a chromatic color by adding white
to it.
Transmissive Media:
A media through which light is transmitted, such as a slide,
negative or transparency. The colors in this type of media
tend to be brighter and richer than reflective media. See
also Reflective Media.
Transparency, Museum Quality:
A very high quality transparency, skillfully shot so that
the lighting is completely even and controlled, and lacking
specular highlights. This transparency is used as the analog
source of a digital master when a piece of art is too large
to scan, since most scanners cannot digitize large, dimensional
pieces.
Value:
The lightness or darkness of a color, outside the chroma or
hue. In terms of value, all colors are either high, middle
or dark. Two visually similar hues may appear similar in chromatic
brilliance, such as red and yellow, but at opposite ends of
the value scale (yellow being of high value and red being
of a dark value, when in the absence of chroma, one would
appear as white, the other would appear as black).
Wavelet Compression:
A mathematical expression that encodes an image as a continuous
stream, thereby avoiding the tendency towards visible artifacts
that result from DCTs division of an image into discreet compression
packages. Wavelets yield a 20% greater reduction in a saved
file size than JPG's DCT method. Wavelets sometimes encode
multiple images at different resolutions within the same formatted
package, much the way Photo CD does, enabling you to open
the image at different sizes and resolutions. Wavelets can
encode images in a lossless form, and a lossy form. See also
JPG2000, JPG, STN.
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