Spectrophotometric Examination of Rough Print Surfaces

Abstract

• The objective was to assess the impact of the surface texture of individual creative paper types (coated or patterned) on the quality of printing and to identify to what extent the various creative paper types require specific types of spectrophotometers. We used stereomicroscopic images to illustrate unprinted and printed surfaces of creative paper types. Surface roughness was measured to obtain data on the unevenness of surfaces. Spectrophotometric tests were used to select the most suitable spectrophotometer from meters with different illumination setup for testing any given print. For the purpose of testing, we used spectrophotometers which are commonly available generally used to test print products for colour accuracy. With the improvement of measuring geometries, illumination setup, colour measurement becomes more and more capable of producing reliable results unaffected by surface textures. Our tests have proved this fact by showing that the GretagMacbeth Spectrolino with annular illumination is less sensitive to surface texture than the X-Rite Spetrodensitometer and the Techkon SpetroDens with directional illumination. Further tests have brought us to the conclusion that there is a difference even between the two devices with directional illumination. While the X-Rite 530 Spectrodensitometer is more suitable for testing coated surfaces, the Techkon SpectroDens can come close to ΔE*ab values produced by the annular illuminated device for textured surfaces.