An essential tool for use in digital photography, the Gray Cards are a reference point used to estimate chromatic balance and image density.
Inside each packet are two Gray Cards; one 20x25cm the other 10x12cm which have 18% reflectance across the visible spectrum.
The cardboard is 2mm thick, this flatness ensures the card appears neutral under any illuminant. The Uncalibrated white reverse side of the cards which have 90% reflectance can be useful for obtaining a quick custom white balance setting.
Take care of the Gray Card keeping it clean and avoid scratches, otherwise over a period of time its reference characteristics and the initial data will be altered.
Silvestri Gray Cards have been certificated by the Istituto Nazionale di Ottica di Arcetri in Florence.
Calibration was carried out using high precision instrumentation, and the indicated data were measured at various wave lengths and with different lightings. code GC004