technical

Paper Profiles

Coated or Uncoated Papers?

Both coated and uncoated paper stocks start out life in a similar way, a dilute suspension of fibres in water is drained through a screen so that a mat of randomly interwoven fibres is produced. Water is removed from the mat of fibres by pressing and drying, then wound onto large rolls which can be cut to a client’s desired size.

Coated papers are produced by applying a fine layer of china clay to the surface of an uncoated sheet during manufacture. This coating covers all the small imperfections in the stock and gives a smooth finish; coatings can be applied more than once to offer an even smoother finish. Once the coating has been applied calendaring rollers buff the paper to increase its smoothness. During this process the paper can be treated to provide different finishes, such as Gloss, Matt and Silk.

Adding a coating to a sheet does affect its bulk; this is due to the coating being denser than the substrate. The higher the level of coating on a sheet, the thinner the sheet will appear, therefore a gloss paper will feel flimsier than an uncoated sheet of the same weight. Sheets with a heavier coating generally are smoother and therefore absorb less ink, leading to quicker drying times because less ink is needed to attain the required ink density.

Uncoated papers tend to act as a sponge and may need larger amounts of ink to attain their required densities. This extra ink can create a more noticeable dot gain when compared to a coated stock; therefore imagery printed on uncoated papers can look flat and lifeless. This can put a printer in a tricky predicament when trying to predict 4 colour results. One way to compensate for this is by using an uncoated profile at the pre-press stage. The profile adjusts high levels of ink being placed in concentrated areas. This is done by lowering the key element and increasing the cyan, magenta and yellow colours. Adjusting the profile reduces the build-up of ink and therefore produces a sharper image. Uncoated papers do, however, offer a far softer and more natural finish that recently has become extremely popular with designers, looking to produce a softer feel.

So in brief, uncoated papers offer a softer and more tactile feel but you do lose a little image quality.

Coated papers produce better quality imagery, have a smooth finish but can feel a little flimsy.  You might want to up the gsm for the text or apply for your FREE DUMMY.

See our folding format PDF