Xerox Nuvera 144 EA roduction Systems Paper Manual - page 14

Selecting stock

Xerox Nuvera

1-8  

Paper Guide

Formation

Formation is the distribution of fibers in paper. Fibers should be distributed evenly throughout 

the sheet. Although formation is not included in the manufacturer’s specifications, you can 

check it by holding a sheet up to a light. If the sheet looks even throughout, it has good 

formation. If you see uneven light and dark areas, formation is poor.

Good formation is especially important when documents include halftone images of 

photographs or high ink coverage. Halftone images appear sharper on paper with good 

formation. Solid images can appear uneven or spotty when printed on paper with poor 

formation.

Impurities

Impurities in the papermaking process can leave tiny specks in some stocks. The specks can 

appear as marks or spots in printed images, especially in high resolution images, fine type and 

fine lines. 

Impurities in recycled papers consist of inks and adhesives (from window envelopes, stick-on 

notes, labels, etc.), which are difficult to remove during the recycling process. Use high quality 

non-recycled papers when the best image quality is required.

Opacity

Opacity refers to the ability of a printed image to show through from the opposite side of a 

sheet or from another sheet below it. Opacity increases as the weight of the sheet increases. 

Fillers are also added to paper during the manufacturing process to increase opacity. 

Opacity is measured according to how much light a sheet blocks and is expressed as a 

percentage between 0 and 100. Most papers fall in the 80 to 90% range, however, an opacity 

of 98% will prevent a printed image from showing through on the opposite side of the sheet.

Choose paper with high opacity when printing on both sides of the paper or when heavy dry ink 

coverage will be applied.

Shade

Shade is the color of the paper. Paper shade may change the colors of printed images because 

dry ink is applied in dot patterns that allow the paper shade to show through. The color of the 

paper (white, pink, buff etc.) must be specified in the Xerox Nuvera Stock Library. When 

choosing paper color remember that paper shades can vary significantly among brands.

Electrical properties and image quality

Resistivity is the resistance to direct current between the two sides of a sheet of paper. The 

electrical properties of paper are important because a sheet must be able to attract dry ink 

during the xerographic process.

If a stock’s resistivity is excessively high or low, the printed image may be too light and 

deletions may occur.