Surface Variance
Mathematical subtraction of one gloss value from another identifies the degree of contrast or change in light reflection across a printed surface. The delta gloss units represent the difference between the unprinted paper and the inked areas or between two different production batches. This metric helps practitioners evaluate the visual impact of a coating or varnish.
Instrumental Calculation
Gloss meters measure the amount of light reflected at a specific angle (usually 60 or 75 degrees for paper). To find the delta, a technician records the base sheet reflectance and then measures the printed image. A high delta indicates a sharp pop where the ink appears much shinier than the substrate.
Visual Consistency
Brand owners often specify a maximum allowable deviation to ensure packaging looks identical across different print runs. Large shifts in these units can make a product look dull or inconsistent when displayed under store lighting. Monitoring this value allows press operators to adjust ink density or drying parameters to meet the required standard.
In many cases, the printer will use a gloss coating to mask the differences between the ink and the substrate. This practice ensures that the final product has a uniform appearance even when using lower grade paperboards.
