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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.