In digital imaging systems, color management is the controlled conversion between the color representations of various devices, such as image scanners, digital cameras, monitors, TV screens, film printers, computer printers, offset presses, and corresponding media.

The primary goal of color management is to obtain a good match across color devices; for example, the colors of one frame of a video should appear the same on a computer LCD monitor, on a plasma TV screen, and as a printed poster. Color management helps to achieve the same appearance on all of these devices, provided the devices are capable of delivering the needed color intensities.

Parts of this technology are implemented in the operating system (OS), helper libraries, the application, and devices. A cross-platform view of color management is the use of an ICC-compatible color management system. The International Color Consortium (ICC) is an industry consortium that has defined:

• An open standard for a Color Matching Module (CMM) at the OS level
• color profiles for:
  • Devices, including devicelink-profiles that represent a complete color transformation from source device to target device
  • Working spaces, the color spaces in which color data is meant to be manipulated

There are other approaches to color management besides using ICC profiles. This is partly due to history and partly because of other needs than the ICC standard covers. The film and broadcasting industries make use of many of the same concepts, but they more frequently rely on boutique solutions. The film industry, for instance, often uses 3D LUTs (lookup table) to represent a complete color transformation. At the consumer level, color management currently applies more to still images than video, in which color management is still in its infancy.^[1]

Hardware[link]

Characterization[link]

To describe the behavior of various output devices, they must be compared (measured) in relation to a standard color space. Often a step called linearization is performed first, to undo the effect of gamma correction that was done to get the most out of limited 8-bit color paths. Instruments used for measuring device colors include colorimeters and spectrophotometers. As an intermediate result, the device gamut is described in the form of scattered measurement data. The transformation of the scattered measurement data into a more regular form, usable by the application, is called profiling. Profiling is a complex process involving mathematics, intense computation, judgment, testing, and iteration. After the profiling is finished, an idealized color description of the device is created. This description is called a profile.

Calibration[link]

Calibration is like characterization, except that it can include the adjustment of the device, as opposed to just the measurement of the device. Color management is sometimes sidestepped by calibrating devices to a common standard color space such as sRGB; when such calibration is done well enough, no color translations are needed to get all devices to handle colors consistently. This avoidance of the complexity of color management was one of the goals in the development of sRGB.

Color profiles[link]

Embedding[link]

Image formats themselves (such as TIFF, JPEG, PNG, EPS, PDF, and SVG) may contain embedded color profiles but are not required to do so by the image format. The International Color Consortium standard was created to bring various developers and manufacturers together. The ICC standard permits the exchange of output device characteristics and color spaces in the form of metadata. This allows the embedding of color profiles into images as well as storing them in a database or a profile directory.

Working spaces[link]

Working spaces, such as sRGB, Adobe RGB or ProPhoto are color spaces that facilitate good results while editing. For instance, pixels with equal values of R,G,B should appear neutral. Using a large (gamut) working space will lead to posterization, while using a small working space will lead to clipping.^[2] This trade-off is a consideration for the critical image editor.

Color transformation[link]

Color transformation, or color space conversion, is the transformation of the representation of a color from one color space to another. This calculation is required whenever data is exchanged inside a color-managed chain. Transforming profiled color information to different output devices is achieved by referencing the profile data into a standard color space. It is easy to convert colors from one device to a selected standard and from that color space to the colors of another device. By ensuring that the reference color space covers the many possible colors that humans can see, this concept allows one to exchange colors between many different color output devices. Color transformations can be represented by two profiles (source profile and target profile) or by a devicelink profile.

Profile connection space[link]

In the terminology of the International Color Consortium, a translation between two color spaces can go through a profile connection space (PCS): Color Space 1 → PCS (CIELAB or CIEXYZ) → Color space 2; conversions into and out of the PCS are each specified by a profile.^[3]

Gamut mapping[link]

Since different devices don't have the same gamut, they need some rearrangement near the borders of the gamut. Some colors must be shifted to the inside of the gamut, as they otherwise cannot be represented on the output device and would simply be clipped. For instance the dark highly saturated purplish-blue color of a typical computer monitor’s “blue” primary is impossible to print on paper with a typical CMYK printer. The nearest approximation within the printer’s gamut will be much less saturated. Conversely, an inkjet printer’s “cyan” primary, a saturated mid-brightness greenish-blue, is outside the gamut of a typical computer monitor. The color management system can utilize various methods to achieve desired results and give experienced users control of the gamut mapping behavior.

Rendering intent[link]

When the gamut of source color space exceeds that of the destination, saturated colors are liable to become clipped (inaccurately represented), or more formally burned. The color management module can deal with this problem in several ways. The ICC specification includes four different rendering intents: absolute colorimetric, relative colorimetric, perceptual, and saturation.^[3][4]

Absolute colorimetric 

Absolute colorimetry and relative colorimetry actually use the same table but differ in the adjustment for the white point media. If the output device has a much larger gamut than the source profile, i.e., all the colors in the source can be represented in the output, using the absolute colorimetry rendering intent would "ideally" (ignoring noise, precision, etc.) give an exact output of the specified CIELAB values. Perceptually, the colors may appear incorrect, but instrument measurements of the resulting output would match the source. Colors outside of the proof print system's possible color are mapped to the boundary of the color gamut. Absolute colorimetry is useful to get an exact specified color (e.g., IBM blue), or to quantify the accuracy of mapping methods.

Relative colorimetric 

The goal in relative colorimetry is to be truthful to the specified color, with only a correction for the media. Relative colorimetry is useful in proofing applications, since you are using it to get an idea of how a print on one device will appear on a different device. Media differences are the only thing you really would like to adjust for. Obviously there has to be some gamut mapping going on also. Usually this is done in a way where hue and lightness are maintained at the cost of reduced saturation. Relative colorimetric is the default rendering intent on most systems.

Perceptual and Saturation 

The perceptual and saturation intents are where the results really depend upon the profile maker. This is even how some of the competitors in this market differentiate themselves. These intents should be created by the profile maker so that pleasing images occur with the perceptual intent while eye-catching business graphics occur with the saturation intent. This is achieved through the use of different perceptual remaps of the data as well as different gamut mapping methods. Perceptual rendering is recommended for color separation.

In practice, photographers almost always use relative or perceptual intent, as for natural images, absolute causes color cast, while saturation produces unnatural colors.^[4] Relative intent handles out-of-gamut by clipping (burning) these colors to the edge of the gamut, leaving in-gamut colors unchanged, while perceptual intent smoothly moves out-of-gamut colors into gamut, preserving gradations, but distorts in-gamut colors in the process. If an entire image is in-gamut, relative is perfect, but when there are out of gamut colors, which is more preferable depends on a case-by-case basis.

Saturation intent is most useful in charts and diagrams, where there is a discrete palette of colors that the designer wants saturated to make them intense, but where specific hue is less important.

Implementation[link]

Color management module[link]

Color matching module (also -method or -system) is a software algorithm that adjusts the numerical values that get sent to or received from different devices so that the perceived color they produce remains consistent. The key issue here is how to deal with a color that cannot be reproduced on a certain device in order to show it through a different device as if it were visually the same color, just as when the reproducible color range between color transparencies and printed matters are different. There is no common method for this process, and the performance depends on the capability of each color matching method.

Some well known CMMs are ColorSync, Adobe CMM, LittleCMS, and ArgyllCMS.

Operating system level[link]

Apple's Mac operating systems have provided OS-level color management since 1993, through ColorSync.

Since 1997 color management in Windows is handled at the OS level through an ICC color management system. Beginning with Windows Vista, Microsoft introduced a new color architecture known as Windows Color System.^[5] WCS supplements the Image Color Management (ICM) system in Windows 2000 and Windows XP, originally written by Heidelberg.^[6][7]

Operating systems that use the X Window System for graphics use ICC profiles, and support for color management on Linux, still less mature than on other platforms, is coordinated through OpenICC at freedesktop.org and makes use of LittleCMS.

File level[link]

Certain image filetypes (TIFF and Photoshop) include the notion of color channels for specifying the color mode of the file. The most commonly-used channels are RGB (for display and printing) and CMYK (for commercial printing). An additional alpha channel may specify a transparency mask value. Some image software (such as Photoshop) perform automatic color separation to maintain color information in CMYK mode using a specified ICC profile such US Web Coated (SWOP) v2.

Application level[link]

As of 2005, most web browsers ignored color profiles.^[8] Notable exceptions were Safari, starting with version 2.0, and Firefox starting with version 3. Although disabled by default in Firefox 3.0, users can enable ICC v2 and ICC v4 color management by using an add-on^[9] or setting a configuration option.^[10] Starting from Firefox 3.5 color management is enabled by default only for tagged images, although support is limited to ICC v2 profiles owing to a change in color management systems from 3.0.^[11] Firefox 8.0 has ICC v4 profiles support. Internet Explorer 9 is the first Microsoft browser to partly support ICC profiles, but it does not render images correctly according to the Windows ICC settings (it only converts non-sRGB images to the sRGB profile) and therefore provides no real color management at all. As of 2011, Google Chrome does not support color management by default.

See also[link]

• Color chart
• Digital printing
• International Color Consortium
• IT8
• Linux color management

References[link]

Further reading[link]

• Fraser, Bruce; Bunting, Fred; Murphy, Chris (2004). Real World Color Management. Berkeley, CA, USA: Peachpit Press. ISBN 0-201-77340-6. 
• Swartz, Charles S. (2004). Understanding Digital Cinema: A Professional Handbook. Focal Press. ISBN 978-0-240-80617-4. 
• Morovic, Jan (2008). Color Gamut Mapping. Wiley. ISBN 978-0-470-03032-5. 

External links[link]

• Color management and color science: Introduction by Norman Koren.
• ColorWiki by Steve Upton.
• Web browser color management guide.
• Using 3D LUT Calibration by Light Illusion.

John Paul Caponigro (born June 23, 1965 Boston) is an Environmental Fine Art Landscape Photographer. He is the son of the American photographer Paul Caponigro and Eleanor Caponigro a graphic designer.^[1] John Paul attended Yale University, and the University of California, Santa Cruz where he was trained as a painter and later as a photographer. After college John moved to Maine and became an artist in residence at The Center for Creative Imaging.^[2] John now works with photo-based digital imaging as his primary medium. Dan Steinhardt of Epson considers John Paul "...one of the great mentors of the photographic medium".^[3] The American photographer Joyce Tenneson has said, "John Paul Caponigro is the rare combination of gifted artist and master technician. He works from the heart to create images that are poetic and evocative, and at times, mystical. He is someone whose sensitivity and intelligence work to break new ground, and someone I will enjoy watching in the years to come.".^[4] He has been awarded membership into many photographic organizations including the Photoshop Hall of Fame,^[5] the Epson Stylus Pros,^[6] Xrite Coloratti,^[7] and the Canon Explorers of Light.^[8] His work crosses the lines between photography and painting and displays knowledge of painterly composition and color theory, coupled with content of modern science, psychology, primal cultures, and the environment.^[2] The photographer Arnold Newman stated,"...Caponigro's mysterious and magical images go beyond reality or surrealism. He has created a wonderful new world of his own".^[9] John Paul Caponigro lives in Cushing, Maine with his photographer wife Arduina, and their son.

Exhibits[link]

From 1990 to 2011 John Paul Caponigro has had over 110 group and solo shows.^[10] He has shown internationally in Italy at the Museo Archeologico Regionale, Val d’Aosta,^[11] and the VIR, SpA, Milan. John has shown his work in the United States in galleries and museums such as the Palm Beach Photographic Centre Museum, Delray Beach, FL and the Pingree Gallery in East Hampton, NY, and the Pasadena Museum of California Art, CA. He has a yearly gallery showing of his newest work each August at his gallery/studio in Cushing, ME.^[12]

Collections[link]

John Paul's photographic work is included in corporate and museum collections. These include Estée Lauder and Pfizer, Princeton University and The Museum of Fine Arts Houston. The Smithsonian Museum of American National History has a collection of John Paul's work that includes one of every media that he has used. This collection includes his early silver gelatin prints, his current pigmented ink prints, preliminary sketches and his print-on-demand books. The Smithsonian is also collecting the tools he uses to produce his work, this includes his software, computers, printers, cameras and cell phones.^[13]

John interviewed over 40 of the great American photographers from 1995 through 2007. These dialogs were published in Camera Arts Magazine the audio tapes of which are now archived at the Eastman House Library, Rochester New York. The transcripts of these dialogs can be viewed on John Paul Caponigro's website.

Lectures[link]

John Paul Caponigro lectures at trade-shows, professional organizations, educational institutions, and corporations, including: MIT, Penn State, RIT, Microsoft, Photo Plus, ASMP and Photoshop World. In 2010 John spoke on creativity for TEDx Dirgo.^[14]

Awards[link]

In 2002 Caponigro won the honor of being voted one of Zoom Magazine's 15 Best Artists of Past 30 Years.^[15] In 2003 he was Photo District News' Annual Winner,^[16] and in 2008 he won the Communication Arts Award of Excellence.^[17]

Workshops[link]

Caponigro runs International and American landscape workshops. He has traveled to Antarctica 3 times ^[18] leading photographic workshops. Pieces of his Antarctica work have been shown at the Peabody Essex Museum in Salem Massachusetts in 2008.^[19] He has done workshops in South Africa and Namibia, and works with Focus on Nature in Iceland doing workshops with them since 2008. In 2010 John and fellow Canon Explorer of Light photographer, Seth Resnick, began running international workshops together through Digital Photo Destinations, an international field workshop company which holds workshops in Antarctica, Greenland and Patagonia. His American field destination workshops included desert destinations such as White Sands, New Mexico, Arches National Park in Utah, Death Valley,CA and Santa Fe, New Mexico. John teaches field photography workshops on Maine Islands, and Maine Fall Foliage out of his studio in Cushing, Maine.

Next Step[link]

John runs printing and creativity workshops out of his Maine studio. Known as a master printer ^[20] he offers printing workshops for students who wish to turn their images into fine art prints. The John Paul Caponigro Next Step Alumni Group was formed in 1998 when a handful of students requested custom workshops to increase their photographic creativity.^[21] The Next Step group has grown from this small body of students to just under 100 photographers. Membership into this group is by invitation only, and group dynamics are a factor in nomination. The Next Step group have held exhibitions of their work at the Maine Media Workshop in Rockland, Maine ^[22] and at the Renaissance Gallery in Carmel, Indiana.^[23] They have produced two books on their work.^[24]

Books / Articles/ DVD's[link]

John Paul's art is the subject of published articles and books on photography and creativity. A Camera Arts article by Sean Kernan in 1999, Paul Slaughters 2007 AfterCapture article,^[25] and a 2010 Scott Sheppard Nik Radio interview,^[26] discuss John's creative process. His images have been included in over 20 books on Fine Art Photography.^[27]

John Paul contributes to photographic and news publications. These include - Camera Arts, Digital Photo Pro, Apple,^[28] and The Huffington Post.^[29] In 2000 Adobe Press published his first book "Adobe Master Class". It was followed up with a second printing in 2003.^[30] This book describes techniques and use of digital technology for artistic purposes. He has also self-published catalogs of his work.^[31] John has authored ten DVDs on Photoshop techniques through Acme Educational,^[32] a digital media learning resource.

Reading[link]

John Paul Caponigro started his website Illuminating Creativity in 2005. The educators website includes information on his workshops, seminars, books, DVDs, prints, gallery exhibits, links to environmental groups, a current calendar of lectures and seminars and the artists' curriculum vitae. The website includes downloadable PDF's on creativity, printing and photographic techniques and bookmaking.

References[link]

External links[link]

• www.johnpaulcaponigro.com
• www.digitalphotodestinations.com
• http://jpc.acmeeducational.com/jpc/index.html
• http://www.focusonnature.is/page/John_Paul_Caponigro_Destination_Iceland

Paul Caponigro (born December 7, 1932), is an American photographer.

Photography career[link]

Caponigro was born in Boston, Massachusetts. He studied with Minor White and has been awarded two Guggenheim Fellowships and three grants from the NEA. His best known photograph is Running White Deer. Caponigro's first one-man exhibition took place at the George Eastman House in 1958. In the 1960s Caponigro taught photography part-time at Boston University while consulting the Polaroid Corporation on various technical research.

In 1971, his work was exhibited in group exhibition "Le Groupe Libre Expression : Expo 5", presented by Jean-Claude Gautrand, at Les Rencontres d'Arles festival, France.

Caponigro's work is included in the collections of the Guggenheim, Whitney, Norton Simon Museum, Museum of New Mexico and San Francisco Museum of Modern Art. His son, John Paul Caponigro, is a noted digital photographic artist.

Quotes[link]

• “I often see the materials of photography as being a type of terrain. Emulsions, liquid developers, silver salts, and fixers interact, and I construct a landscape that I need to first explore in my mind’s eye if I am to make it manifest as an artful image in silver.”
• "Photography is a medium, a language, through which I might come to experience directly, live more closely with, the interaction between myself and nature."
• "At the root of creativity is an impulse to understand, to make sense of random and often unrelated details. For me, photography provides an intersection of time, space, light, and emotional stance. One needs to be still enough, observant enough, and aware enough to recognize the life of the materials, to be able to 'hear through the eyes'."

Books[link]

• Veiled Yet Revealed: Masterworks from Fifty Years
• Paul Caponigro: Masterworks of Forty Years
• Paul Caponigro - New England Days
• Paul Caponigro: Of the Earth, Still Life Studies 2001~2004
• Megaliths
• [New England Days ISBN 978-1-56792-216-5]
• [Landscape ISBN 978-0-07-009780-3]
• [The Wise Silence ISBN 978-0-8212-1548-7]
• Sunflowers

External links[link]

• Artcyclopedia, Paul Caponigro
• Amico Public Collection