Dan Margulis
Encyclopedia
Dan Margulis is an expert on color correction and reproduction of photographs, using Adobe Photoshop
or similar software.
His Professional Photoshop series (first edition 1994, currently in its fifth edition, 2006) is widely viewed as an authoritative work in the field of digital color correction of photographs. His Photoshop LAB Color: The Canyon Conundrum and Other Adventures in the Most Powerful Colorspace established the usage of L*a*b*
as a standard part of the repertory of high-end retouchers. His magazine column, Makeready, which ran from 1993 to 2006, introduced many concepts in color handling that have since become accepted practice in the industry. The column appeared in several publications worldwide. In its later years, it was carried simultaneously by Electronic Publishing and Photoshop User magazines in the United States.
His techniques attempt to emulate certain well-known reactions/attributes of the human visual system
, such as chromatic adaptation
and simultaneous contrast
. He has identified several other characteristics of human perception
that he states should be taken into account when processing a digital image. These include assertions that humans prefer fuller and richer tonality in the quartertone region than cameras customarily provide, that humans subconsciously use saturation as a measure of an object's distance, and that humans do not focus on strongly colored objects as intensely as on more neutral ones.
Other theoretical suggestions made by Margulis include:
Image-processing techniques originated by Margulis include
At a presentation to MIT faculty and graduate students in 2007, Margulis introduced the "picture-postcard workflow", which he claimed to yield better correction results in shorter times than did traditional methods of image enhancement. He proposed a three-stage approach. First, any obvious problems with color are corrected. Second, contrast is enhanced without changing the color of the first step. Third, more pleasing color is incorporated, usually in LAB. The proposal suggested replacing the traditional method of color correction, where one step is intended to solve color and contrast problems simultaneously.
In 2001, Margulis was one of the first three members, and the only writer, inducted into the Photoshop Hall of Fame. In the United States, his small-group, hands-on courses in these subjects are sponsored by Sterling Ledet & Associates, Inc.
In Europe, he has taught in German, Italian, Spanish and English.
Adobe Photoshop
Adobe Photoshop is a graphics editing program developed and published by Adobe Systems Incorporated.Adobe's 2003 "Creative Suite" rebranding led to Adobe Photoshop 8's renaming to Adobe Photoshop CS. Thus, Adobe Photoshop CS5 is the 12th major release of Adobe Photoshop...
or similar software.
His Professional Photoshop series (first edition 1994, currently in its fifth edition, 2006) is widely viewed as an authoritative work in the field of digital color correction of photographs. His Photoshop LAB Color: The Canyon Conundrum and Other Adventures in the Most Powerful Colorspace established the usage of L*a*b*
Lab color space
A Lab color space is a color-opponent space with dimension L for lightness and a and b for the color-opponent dimensions, based on nonlinearly compressed CIE XYZ color space coordinates....
as a standard part of the repertory of high-end retouchers. His magazine column, Makeready, which ran from 1993 to 2006, introduced many concepts in color handling that have since become accepted practice in the industry. The column appeared in several publications worldwide. In its later years, it was carried simultaneously by Electronic Publishing and Photoshop User magazines in the United States.
Body of work
The work of Margulis is associated with the concept that digital color correction should seek to correspond to what a human observer would see if placed in the position of the camera. He popularized, but did not originate, a method he described as "color by the numbers", which requires the retoucher to verify that certain values in the digital file agree with known standards.His techniques attempt to emulate certain well-known reactions/attributes of the human visual system
Visual system
The visual system is the part of the central nervous system which enables organisms to process visual detail, as well as enabling several non-image forming photoresponse functions. It interprets information from visible light to build a representation of the surrounding world...
, such as chromatic adaptation
Chromatic adaptation
Chromatic adaptation is one aspect of vision that may fool someone into observing a color-based optical illusion, such as the same color illusion.An object may be viewed under various conditions. For example, it may be illuminated by sunlight, the light of a fire, or a harsh electric light...
and simultaneous contrast
Contrast effect
A contrast effect is the enhancement or diminishment, relative to normal, of perception, cognition and related performance as a result of immediately previous or simultaneous exposure to a stimulus of lesser or greater value in the same dimension...
. He has identified several other characteristics of human perception
Perception
Perception is the process of attaining awareness or understanding of the environment by organizing and interpreting sensory information. All perception involves signals in the nervous system, which in turn result from physical stimulation of the sense organs...
that he states should be taken into account when processing a digital image. These include assertions that humans prefer fuller and richer tonality in the quartertone region than cameras customarily provide, that humans subconsciously use saturation as a measure of an object's distance, and that humans do not focus on strongly colored objects as intensely as on more neutral ones.
Other theoretical suggestions made by Margulis include:
- In conversions from color to black and white, the objective is to identify areas of contrasting color and adjust them to substitute contrast in luminosityLuminosityLuminosity is a measurement of brightness.-In photometry and color imaging:In photometry, luminosity is sometimes incorrectly used to refer to luminance, which is the density of luminous intensity in a given direction. The SI unit for luminance is candela per square metre.The luminosity function...
. - Identification of the A channel of L*a*b*Lab color spaceA Lab color space is a color-opponent space with dimension L for lightness and a and b for the color-opponent dimensions, based on nonlinearly compressed CIE XYZ color space coordinates....
(usually written as LAB by imaging professionals) as operating on a magenta-green axis, as opposed to the red-green axis described in previous technical works.
Image-processing techniques originated by Margulis include
- The concept of assigning important image regions to the steepest parts of input-output channel curves ("The steeper the curve, the more the contrast.")
- Use of channel blending to enhance detail in weaker channels.
- Overlay blending to enhance highlight and/or shadow detail.
- Using different styles of black generation (gray component replacement, or GCRGrey component replacementWithin the CMY color space, any hue angle can be achieved by combining two of the three primaries. The intention of the third color is to move that hue towards grey , and is known as the greying agent. However, as that greying agent has an inherent hue of its own, it also shifts the hue as it...
) to avoid press problems or to make color correction easier. - Unsharp masking by channel rather than overall
- Emphasizing the darkening function of sharpening at the expense of lightening
- The "Man from Mars Method" of driving colors apart without regard to whether gray balance is altered.
- LAB as a primary tool in color correction
- Blurring the AB channels of LAB to reduce colored noise.
- Assigning a "false profile" to an RGB image so that it will be interpreted as lighter during subsequent conversions.
- High Radius, Low Amount ("hiraloam") method of unsharp masking
- Uniting separate versions of the same image through use of masks that, although based on the original photograph, have been blurred beyond recognition.
At a presentation to MIT faculty and graduate students in 2007, Margulis introduced the "picture-postcard workflow", which he claimed to yield better correction results in shorter times than did traditional methods of image enhancement. He proposed a three-stage approach. First, any obvious problems with color are corrected. Second, contrast is enhanced without changing the color of the first step. Third, more pleasing color is incorporated, usually in LAB. The proposal suggested replacing the traditional method of color correction, where one step is intended to solve color and contrast problems simultaneously.
In 2001, Margulis was one of the first three members, and the only writer, inducted into the Photoshop Hall of Fame. In the United States, his small-group, hands-on courses in these subjects are sponsored by Sterling Ledet & Associates, Inc.
Sterling Ledet & Associates, Inc.
Sterling Ledet & Associates, Inc. is a chain of United States software training centers incorporated in the state of Georgia on August 29, 1996. The company is an authorized training provider for Adobe Systems, Quark, Inc., and Apple Inc.....
In Europe, he has taught in German, Italian, Spanish and English.
External links
- The Makeready Archive, 1993–2006 – abstract for all columns, with links to PDFs of some
- Photoshop Training with Dan Margulis – Articles – assorted articles