Why Calibration?

The aim of color calibration is to measure and/or adjust the color response of a device (input or output) to a known state. In International Color Consortium (ICC) terms, this is the basis for an additional color characterization of the device and later profiling. Color calibration is a requirement for all devices taking an active part of a color-managed workflow.

Calibration Methods

  • Pure software calibration show loss of tonal values and limited quality
  • Combination of software and hardware calibration shows loss of fewest tonal values and semi-professional quality
  • Hardware calibration show no loss of tonal values and professional top quality

Step 1 of hardware calibration

Measure luminance and color of white point and black point using an external sensor and adjustment of the LUT for white point, black point (or Red, Green and Blue point). Tuning of gamma curve (gray shade control).

Step 2 of hardware calibration

Creation of a ICC profile for the operating system (PC/MAC)


ICC Profiles

ICC profile is a set of data that characterizes a color input or output device, or a color space, according to standards promulgated by the International Color Consortium (ICC). Profiles describe the color attributes of a particular device or viewing requirement by defining a mapping between the device source or target color space and a profile connection space (PCS).

More info

www.colormanagement.org

www.eci.org

Color Workflow

The 3D LUT Color Emulation feature of the SpectraView Series can take the ICC profile of any device, e.g. printer, and through uploading via the MultiProfiler software application, define the monitor gamut to that specific ICC profile.


Color Spaces

sRGB (Standard RGB)

  • Defined by Microsoft and Hewlett Packard in 1996
  • Average CRT/LCD monitor color space
  • Suitable for internet and office applications
  • Too small for artwork, not 100% suited for print workflow
  • Contained in Photoshop
  • White point D65
  • Tonal response curve: modified gamma 2.2

Adobe RGB

  • Defined by Adobe in 1998
  • Standard working space in the U.S
  • Contains 98% of all printable colors
  • Contained in Photoshop
  • White point D65
  • Tonal response curve: gamma 2.2

eciRGB_v2

  • Defined by Color Solutions in 2005
  • Standard working space in Europe (see www.eci.org)
  • ISO standard 22028-2:2007
  • Contains 100% of all printable colors
  • NOT contained in Photoshop
  • White point D50
  • Tonal response curve: L*

L*a*b* (CIELAB)

The L*a*b* system defines the color space with a dimension ‘L’ for lightness and ‘a’ and ‘b’ for the color dimensions based on non-linearly compressed CIE XYZ space coordinates. Changes in colors are similar to human visual perception abilities. It allows precise table profiling and is perfectly suited to exceptionally accurate 14-bit LUT hardware calibration capability of the SpectraView series.

Other RGB spaces

  • CIE-RGB: mercury spectrum
  • PAL, SECAM, NTSC: TV Standards, phosphor
  • ProPhoto RGB: digital photography
  • Wide Gamut RGB
  • DonRGB
  • sRGB / dsRGB
  • Adobe RGB
  • eciRGB_v2
  • L*a*b*

3D Look-Up Tables

The integrated 3D LUT with color emulation preset within the SpectraView series of products, can be used to transform the color space of the monitor to emulate that of the printer, or other color workflow device. The 3D LUT is a three dimensional table that maps colors into a different color space. The Color Processing Engine in the SpectraView series of products allows complex color gamuts such as those of color printers to be emulated on the monitor directly. This allows print previews to be performed with applications that do not support this feature directly. The MultiProfiler application can easily load ICC Profiles into the 3D Look Up Tables.


Wide Color Gamut

Experience the very best in color image quality with the latest generation of state-of-the-art 10-bit LCD technologies, with exceptionally wide viewing angle, widest color gamut available and absence of color shift. The true benefit of a wide color gamut display is particularly visible when combined with 10-bit panel, since potential color banding or visible grayscale steps are eliminated.

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SpectraViewII Software

Designed for professionals with color-critical applications, SpectraViewII combines award-winning NEC display technology with a color-measurement sensor and sophisticated calibration software. The result is highly accurate, reliable, repeatable, feature-rich solution for display calibration and profiling.

The SpectraViewII system uses a color sensor to take color measurements of the display screen during calibration. The software analyzes these measurements and sends color adjustment commands directly to the display monitor. This means that color adjustments are made in the monitor rather than in the video graphics adapter. With SpectraViewII, the video graphics adapter is not used at all to make any gamma or Tone Response Curve corrections to the display, so the fidelity of the system is maintained.

SpectraViewII is available on Apple Mac OS, Microsoft Windows, and several Linux distributions.

You can download the current version of the SpectraViewII software as well as registration and licencing here.