Adjustments For Paper Brightness
The brightness of paper or any other substrate has a bearing on the contrast level of the printed color reproduction. During papermaking, the use of brightening agents is monitored to achieve a desired light reflectance measured at 457 manometer. This blue light reading determines the brightness of the substrate. Natural wood pulp color has a yellow cast that is neutralized with blue dyes and, in some cases, by fluorescing agents.
The many different available grades of paper yield different levels of brightness. In packaging it is common to select foils, plastic, and films based on durability and barrier characterisitics rather than brightness or whiteness. Many of these non-paper substrates are coated with a white base that provides for the whiteness and brightness factors. Always zero a densitometer to the substrate prior to reading color densities.
Edity by Vikas 9 April, 2012
