The Key to Accurate Color Viewing
The following post was submitted by Color 2015 sponsor, GTI Graphic Technology, Inc.
What do a photographer, commercial printer, and sign printer have in common? They all have a need to accurately communicate color. When they carry out this objective consistently and accurately, they are providing a high level of value to their clients and increasing the efficiency of their business.
Reproducing color accurately is a complicated process, especially when different substrates, technologies, and production facilities are involved. To help ensure that accuracy is achieved, viewing comparisons across the supply chain should be made in viewing conditions that comply with the ISO 3664:2009 standard.
ISO 3664:2009 is the international color viewing standard for the graphic technology and photography industries. It is a set of specifications that enables lighting engineers and manufacturers to design, test, and certify their color viewing systems to the industry standards and challenges them to enhance the performance of their products. There are five specific conditions to meet when designing an ISO 3664:2009-compliant viewing booth.
- Color Quality
D50 light, which represents natural daylight, is used to view prints, photographs, and other graphic arts applications. It should be noted that not all 5,000K lamps are equal. To maintain compliance with the standard, use only ISO 3664:2009-compliant lamps in your viewing booth.
- Light Intensity
Consistent light intensity is critical to consistent image rendition. The standard provides a target intensity designed to allow full tonal visibility of shadow detail without washing out highlights. Color decisions should be under light that is between 1,750 and 2,250 lux, with 2,000 lux being optimum.
Even light intensity across an image assures correct interpretation of print/reproduction quality. Evenness is ensured by measuring illuminance at several evenly distributed points on the viewing surface. Illumination should be at least 1,200 lux (60% of 2,000) intensity at all points on the viewing surface.
Surround color and reflectance affect color appearance. ISO 3664:2009 specifies that the surround and backing shall be neutral and matte. Munsell N8/ neutral gray paint is used by GTI Graphic Technology, Inc., the leading manufacturer of color viewing systems to meet this condition.
The presence of excessive glare is distracting and can hide reproduction detail. Therefore, the light source, image, and the observer’s eyes need to be positioned to minimize glare. The standard does not explicitly specify lighting geometry but states it should be minimized.