Abstract: Stabilized lighting devices that simulate the standard illumination sources of the International Commission on Illumination (CIE) are in demand both in industry and in research. The main requirement for lighting devices to create standard viewing conditions in the printing industry is the compliance of the lighting spectrum with the standard illuminator D50 (CIE). The level of illumination, uniformity in a given field, etc. are also important parameters, but their values are determined by the specifics of the task. Light sources with a specific spectrum equivalent to D50, are specialized expensive products, usually with limited operational resource. The most common is specialized fluorescent lamps (FL). Xenon discharge lamps are mainly used for flash lighting. Light emitting diodes (LEDs) that are spectrally close to D50 are still not widely spread. However, it is possible to obtain the required spectrum in a hybrid illuminator. Controlled narrowband LEDs allows to complement the standard FL spectrum in specified areas in order to obtain a good D50 simulator. The paper describes a developed stationary lighting device – a viewing box equipped with a hybrid multispectral light source, based on FL (close to the standard F1 CIE illuminator), narrow-band LEDs (390, 410, 445, 490, 515, 595, 630 and 660 nm) and “warm white” LED (CCT 2800 K). The LED brightness is controlled by an electronic digital control system using pulse width modulation (frequency of about 400 Hz). Achieved targets that are fully compliant with ISO 3664: 2009. Based on the solutions used, it is possible to arrange lighting with a CIE D-series illuminators spectrum equivalent he in large rooms. It can be required when studying visual perception.
Index terms: lighting spectrum, standard illuminator, viewing conditions, light emitting diode, fluorescent lamp.