A screen preview is not a production color

A color on a screen is a display of a file under that screen's conditions. A color on a product is light coming from a physical surface. Those are different observations. Treating the screen as the specification hides the conditions a maker needs in order to judge a match.

Name the object you are judging

ISO 3664:2025 specifies viewing conditions for images on reflective and transmissive media, such as photographic and photomechanical prints and transparencies. Its scope includes critical comparison, appraisal of tone and color at illumination levels similar to practical use, including routine inspection, and some comparisons that use projected transparencies.

The same standard says it does not apply to soft-proofing displays, to paper manufacture, or to applications outside graphic technology and photography. A monitor preview sits outside that viewing-condition standard. A workshop lamp, a phone photo, and a window are not automatically the condition the standard describes either.

If the job is graphic reproduction, say whether the judgment is a critical comparison with a reference or a practical look at the finished print. If the job is outside graphic technology and photography, do not borrow this standard as if it set the viewing condition.

A color number needs a measurement procedure

ISO 13655:2017 specifies procedures for measuring and computing color values for graphic arts images. Its scope includes objects that reflect, transmit, and emit light, such as flat-panel displays. It also covers production printing processes that include offset lithography, letterpress, flexography, gravure, screen printing, and digital printing.

It does not address spectral measurements for other needs, including measurements used while producing printing paper or proofing media. A number from one instrument, backing, light source, or software path is not a universal color identity.

For graphic-arts work, state the measurement procedure when a number will accept or reject the job. For other methods, such as dye on a blank, embroidery thread, a painted part, or a 3D-printed surface, this standard may not apply. Say that the method is outside it instead of implying a match.

Separate the request from the production condition

• Required: the reference the maker should compare when a match matters. That may be an approved physical sample, a named print condition, or a clearly identified file plus the intended substrate.