by clicking the arrows at the side of the page, or by using the toolbar.
by clicking anywhere on the page.
by dragging the page around when zoomed in.
by clicking anywhere on the page when zoomed in.
web sites or send emails by clicking on hyperlinks.
Email this page to a friend
Search this issue
Index - jump to page or section
Archive - view past issues
FLEXO Magazine : February 2008
38 FLEXO FEBRUARY 2008 www.flexography.org Color Science Methods of Measuring and Communicating By Bob Binder We see, feel, and experience color every day. But how do we describe it? "The new corporate logo is a vibrant red or a bright yellow!" "Did you see new lime green ink for the Widget account?" Most of us describe color by developing a mental picture of the color and choosing words to describe it. The person who hears this description of the color formulates a mental picture. But how often do you think the color in mind is exactly the same? Herein lies the issue. Communicating color can be very subjective. Today, most companies are equipped with color measure- ment instruments and software. These color quality assurance systems store standard data and the rules (tolerances) that define a pass/fail characterization of each measured sample. The proper use of these systems turns the subjective evaluation of color into an objective, measurable, and thus controllable characteristic. COMPONENTS OF COLOR Three components are necessary for color to exist---a light source, an object (in our case, the printed material) to interact with that light, and the receiver that interprets that color. This receiver can be a human using his/her eye and brain, or an in- strument using optics and electronics. The materials printed on flexographic presses are reflectors of light. The physical makeup of the printed sheet enables the selective absorption and scatter of light energy. The dyes and pigments used in flexographic inks are engineered to be highly effective absorbers of selected portions of light energy, while reflecting the remainder. Each physical sample has its own re- flectance curve. And just like a human fingerprint, every reflec- tance curve is unique. Sir Isaac Newton discovered that "white" light can be broken down into its individual colors by use of a prism. The prism has the effect of refracting or bending the light's path, splitting white light into its individual components. FIGURE 1. All art courtesy X-Rite Inc. BEGINNER FLEXOGRAPHER TECHNOLOGIES & TECHNIQUES