The common and unusual appearance in offset print plate making reachs a processi
From;    Author:Stand originally

Regard plate making of an offset print as personnel, often can encounter all sorts of unusual situations, according to different situation, want to adopt different processing technique.

One, original density is insufficient

Vitriolic paper density is very common not quite, especially big character and solid plot. Use first commonly add secret agent (add black agent) daub (the place when noticing daub dips in add secret agent cannot too much) , wait for dry hind ability is in same a local daub the 2nd, printing down of the ability after working completely. But sometimes daub increases secret agent density insufficient still, still have two kinds of processing techniques at this moment.

(1) besmear prepared Chinese ink or use black paper cover

Besmear prepared Chinese ink applies to big character and mixedder pattern, apply to with black paper cover on the spot piece. Also can combine look of two kinds of methods, besmear with prepared Chinese ink edge is mixed first namely fine narrow place, cover of reoccupy black paper the rest of chunk is on-the-spot. The attention uses Chinese ink cannot too much, otherwise meeting hair knits vitriolic paper, affect printing down quality.

(2) relapses copy law

With the method that copies repeatedly the film original with attainable enough density. Use less time of exposure and develop time above all (the 70 % of 50 % ~ that are normal time commonly) the copy gets shade pursues, part of the blank in pursueing shade because density is insufficient and what be shown to come is silver-colored grain raze, use this shade figure more time again (the 150 % of 120 % ~ that are normal time commonly) copy the 2nd times, at this moment the film with general attainable enough density. If still insufficient, can reverse beat again can.

2, film has grey fog

Grey mist can be used on film increase time of exposure or develop time, increase the method such as developer solution chroma to handle, but must assure graph article quality. If cannot make sure graph article quality or grey mist are too heavy, also be forced to give film again.

3, literal strokes degree of finish is inhomogenous

This kind of circumstance is common at vitriolic paper, because laser printer breakdown or quality of vitriolic paper itself are bad to cause,be. Usable also daub adds the method of secret agent to ameliorate the difference between the crudest strokes of a Chinese character and the finest strokes, but cannot eliminate quality of work completely inhomogenous phenomenon. At this moment, should maintain printer or change vitriolic paper is delivered again after vitriolic paper.

4, geometry of type page happening is out of shape or size differs

Because printer is adjusted,geometry is out of shape often is undeserved and cause, but also have occurrent. Be out of shape often happen on vitriolic paper, it is the parallelogram is out of shape more, namely the travel of type page, row is not perpendicular relation. Should be out of shape or size differs vitriolic paper can give afresh only when the phenomenon is serious, not serious when can not deliver vitriolic paper again below the condition that imposes so that the client agrees, such, need to rely on cut a side to be with page number for fiducial, fluctuation with type page in the left and right sides when makeup fiducial undertake makeup. Because rely on cut a side with type page,be fiducial, travel overprint forbids an appearance is not very serious, but if with behavior fiducial, row overprint forbids a phenomenon to be met very serious, and should be with a side of type page cut fiducial when, side of spine of a book was opposite neat be discovered not easily.
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