D65 is standardized viewing condition with 6500 K color temperature. It is the default setting for most monitors and is mainly used in color matching etc. for websites, so in media that are considered primarily to be viewed on the monitor.
In the printing industry, the standard light is D50 according to ISO 3664: 2009 standard, a warmer light than D65 with 5000 Kelvin color temperature, which is also used for color matching on the press and in the evaluation of proofs.
The GTI GmbH is beside Just Normlicht a renowned manufacturer of standard light tubes and standardized light consoles and colour cabins. GTI offers numerous systems for colour assessment, but is- other than Just – opposed the use of LED, and therefore offers only special neon-based solutions. LEDs in the standard light industry are according to GTI economically and qualitatively no real alternative to the renown and tested tubes.
The Just Normlicht GmbH is the most famous manufacturer of standard lighting solutions in the printing sector. The company Just from the Swabian Weilheim / Teck sells alongside the classic D50 and D65 standard light tubes and various proof lights, stations and light booths, where prints can be checked under standardized lighting. In recent years, the LED technology has been introduced, so that now several devices with LED technology are offered. Another well-known company is GTI; Standard light tubes are also manufactured by OSRAM and other manufacturers.