Coated paper is a slick, glossy stock best known for magazine, post card and high-end direct mail production. Coated paper is manufactured in the same manner as uncoated paper, with an additional step of adding a thin layer of Kaolin (white clay), a titanium oxide material. Coating paper also is an excellent means of preserving shelf life and making paper more resistant to water and staining. Both manufacturer and customer need to consider this particular option applied to any product. Coated paper has both advantages and disadvantages in production and distribution.
Coated Paper Considerations
As coated paper is "hard," meaning not very porous, ink and other substance on the paper will take longer to dry and set. As such coated paper has a strong tendency to offset on the press. This means wet ink on top of one sheet of paper will be transferred to the back of the next sheet laid on top as the paper comes off the press. To counter this, presses add a thin microscopic layer of powder between each sheet. This acts as both a drying agent and barrier, preventing sheets from coming into direct contact
Coated Paper Advantages
Coated paper with its hard glossy surface makes reproducing photographs and process color images more vibrant and accurate. The brighter and whiter the surface the more accurate the color reproduction, as there is less loss of contrast within the color range of the image. Coated paper also had advantages in the press bindery. Coated paper handles easily when folding, collating, stapling or perfect binding. All these considerations means less time in post press for the printer to speed order completion and quicker delivery time to the customer. Customers see advantages, as presentation pieces and direct-mail material will have greater appeal and greater responsiveness from a targeted audience.
Coated Paper Disadvantages
With the need to print coated paper on presses with additional accessories such as spray powder devices and quick-curing ultraviolet light sources (to speed the ink drying time and reduce opportunities for offset), printing on coated paper can be more expensive per page than printing uncoated stock. Also, coated paper is generally more expensive by weight than uncoated stocks of similar thicknesses. A pound of coated stock will cost more than a pound of uncoated bond. Coated paper also is in many instances not as readily receptive by paper recyclers without separation and special handling.
