Figure 1: Color spaces of three printing standards in AdobeRGB
Figure 2: ColorMaster color space for image reviewing.
Color management is the controlled conversion from one color standard to another and between various devices such as monitors, proofing systems and print presses. Its primary goal is to obtain a visual close match across any output medium, and to meet expectations established when the image was initially approved. And this is where color management often fails, and which subsequently requires additional correction cycles. In fact, the click on a camera is the first step of color management and, far too often, underestimated. The initial approval after an image was taken is by far the most important part of media production. If taken seriously, it can make further correction rounds unnecessary. Insufficient contrast range as well as highlight and shadow detail often originate in the light settings and could be better resolved at its source than by color correcting it at a repro house. Viewing an image in RAW or Adobe RGB on a monitor may raise the wrong expectations, as the conversion to a final output color space would certainly influence the picture areas (Fig. 1). Another challenge of color management is gamut mapping, which is either the clipping or shifting color points of a large color space into a smaller one. Hence, image reviewing based on the output medium’s standard space, instead of Adobe RGB, allows a photographer to immediately compensate for losses.
Printing color spaces, however, varies greatly in size and corner colors; this is why GMG developed its ColorMaster Concept based on the so-called ColorMaster color space (Fig. 2). This color space works like a shell that covers the imaginary entirety of all international output color spaces very closely. Reviewing image files in ColorMaster color space allows a reviewer to estimate image quality independently of the final output color space, yet with a clear indication of what would happen to contrast and color range. It is important to understand that ColorMaster only is used for viewing purposes. All adjustments are always done in an Adobe RGB working space.
During the final step of a media production, images need to be converted to the actual output color space (i.e. GRAcoL 2006, Fogra 39L). For this purpose, the ColorMaster Concept provides conversion profiles to any international printing standard. Each separation profile has been meticulously adapted to visually match the ColorMaster color space as closely as possible.
Brand owners and service providers share one common problem, which seems to be the only constant in the graphic industry: cost and time pressures. Today, we see more printing at less value — shorter print runs to the benefit of multi-channel advertising. Here, proprietary color management solutions (such as GMG ColorMaster Concept) provide solutions that help to cut down correction needs and consequently unnecessary rounds of corrections. By saving time and cost for print media production, repro houses, printers and publishers can broaden their services to a content world that is getting faster and much more diversified.
Color management is moving cross channel
Today, our print industry is fairly sensitive and trained to judge and manage color on static files. We are less sensitive to color on TV screens or on monitors when browsing the Internet for shopping or entertainment. Color management on semiprofessional videos is still in its infancy. This may change as technology and future applications advance. The film and broadcasting industry already spends a lot of effort on managing color on video and film. Here, 3D lookup tables (3D LUTs) are used to represent a complete three-dimensional color transformation. These lookup tables are used to calculate preview colors for a monitor or digital projector of how an image will be reproduced on the final video print. The 3D LUT is a three dimensional lattice of output colors, where each axis represents one of the three input color components and the input color. Not bilinear, but trilinear interpolation is used to approximate the value of an intermediate point, as we are operating in color spaces with dimensions.
For brand owners, the visual tolerances that go along with the jungle of monitors and TV screens that represent color much more randomly has been a disappointment for a long time. Differing levels of development, different monitor back lighting, uncalibrated screens and missing standardization seem to not justify the effort spent on brand videos today. Yet it is not just color under scrutiny, but the entire experience of a scene – sharpness and blur, brightness and contrast, and ramping. (Instead of film being shot at the normal 24 frames-per-second, it is ramped up and shot at 48, or 72, or 96. The more frames per second, the slower the action.) This does not even touch upon tracing and retouching unsightly artifacts. All this is state of the art in film and broadcasting today. Tomorrow it will be here for commercial advertising, and certainly will affect the awareness of LCD and panel producers—and service providers—equally. Self-calibrating TV screens and monitors will become standard, and traditional print repro houses will learn to add multi-channel retouching to their services. There’s a glorious future for those in the industry who are willing to learn about color management in new media. However, a lot of things remain to be done. Stay tuned.