Text 6 Potential problems with paper

Paper is not inert, it reacts to its environment and this may c printing and processing problems. The manufacturing pr< itself can result in minor defects, leading to production prob Some of these are outlined below.

Curl stability Paper is affected dramatically by temper and changes in humidity. Perhaps the one most important factor RH (relative humidity) since this alone will determine whether the sheet will lie flat or expand/contract and even curl. This will have a considerable effect on the end result, particularly if the pr involved requires a high degree of colour registration accuracy. In an ideal situation, the print room should be RH control match that of the paper conditioning environment. This ensure that the moisture content within the paper remains constant and so the sheet will not move. Remember, how that lithography is a 'wet¹ process and the machine minder allow for this.

Linting/picking A common problem with both coated uncoated paper is that of linting, or 'pick'. Usually, this is a problem of debris that is either loose on the surface (bad paper to begin with or cutter dust) or that lifts as a result of the printing process tack pulling particles away from the surface). The overall would be white spots appearing on the printed surface. M< paper making technology has minimized this problem.

Squareness Obviously, to achieve a good print result the must be square. Modern precision cuttingtechnology can prc very accurately- cut sheets and 'out of squareness¹ is rare.

Long edge This is usually a problem associated with 1 weight papers of 60gsm or below and manifests itself slackness on one edge of the reel, caused by differing pi across the paper web during manufacture. This may pr particular problem if different webs are to be matched multi-part continuous stationery.

Bulk after printing Paper is specified prior to printing ar characteristics may change during the print process. 1 particularly true with high bulking book papers wher pressures encountered during printing tend to flatten the and cause a three to five per cent reduction in bulk.

Binding problems As previously mentioned, the prmte binder often require opposing grain directions with paper It is worth remembering that with certain types of format, direction can cause serious binding problems. Probably th example of this is using a heavy, coated paper on a landscape format. The wrong gram direction (across pape cause tremendous strain in the spine and no matter how w book is bound it will eventually begin to break the bindir Obviously, choice of binding material is equally impor should be remembered that publisher, printer and 1 should liaise very closely on all the above points.

Exercises:

I. Read the sentences and say if they are true or false. If they are false, correct them.

II. Find the equivalents of the following terms:

a)

b)

c)

d)

e)

f)

g)

h)

i)

j)

k)

l)

m)

n)

o)

p)

q)

r)

s)

t)

III. Fill the gaps using the following words:

IV. Compare different

V. Write a short summary of the text.