Welcome to our #OKalphabetseries where we visit paper and printing terms daily. Come back each day as we weave our way through the alphabet and share our 110 years of knowledge with you.

M is M-Weight
M Weight refers to the actual weight of 1,000 sheets of paper in a specific basis weight and sheet size. For example, 1,000 sheets of 80 Cover in a 26 x 40 sheet size weighs 320 pounds. Thus, this paper has a 320 mweight.

Welcome to our #OKalphabetseries where we visit paper and printing terms daily. Come back each day as we weave our way through the alphabet and share our 110 years of knowledge with you.

O is Opacity
Opacity is just one of the many properties of a sheet of paper. Opacity measures the amount of light that can be seen through a sheet of paper in values of 1 (the most transparent) through 100 (the most opaque). The higher the opacity of a sheet of paper, the less “show through” of the printing from the opposite side or the sheet below. You'll want to pick a sheet with good opacity when your layout has solids of color, heavy coverage or bold type. When color dyes are added to a sheet, opacity increases. Increasing a paper’s basis weight also increases opacity. The whiteness and smoothness of a sheet tends to decrease opacity. Note, sometimes the amount of printing ink “show through” from the reverse side of a sheet of paper is the result of ink absorption and penetration through the sheet.  Your opacity issue could be optical or structural. Fillers, coatings and formation all affect opacity.