— When from any cause at press, the impression on the paper is smeared, it is said to Slur.
This may arise from many causes — if the tympan joints are loose, it will be produced by the least lateral movement of the tympan after it is turned down — if the ear of the frisket touches the inside of the cheek in running in, it will cause it — if the press runs close, so that the inner tympan touches the face of the platen, it is very likely to slur; and I have often observed this in wooden presses that had been altered to obtain the additional power, for the platen was brought so low and near to the face of the letter in the form, as not to allow room to run in clear. In presses where the tympans are large, if the slur pin does not act, that corner of the tympan will come in contact with the form first, and cause a slur, particularly if the tympans are in any way rickety, or twisted by drawing on the parchment. Where the winter has been justified with cards, to produce a greater spring in the pull, it has been known to produce slurring, The first step towards curing this defect is to ascertain from what cause it arises; and then it is not difficult: but it has often caused great trouble to discover the cause.
The following are my old Pressman's directions “To prevent Slurring and Maculing;” and though it will be perceived that some of them apply only to wooden presses, yet the whole may be useful.
“Exclusively of the aforesaid, there may be many other causes of slurring, which the pressman can only discover by close attention. I have often found cork bearers a great preventive.
“I have heard many complaints of the middle pages of a twelves form maculing at a two-pull press; but this is not always the fault of the press. The cause frequently is owing to blankets being in the tympan which have been used for folios, quartos, octavos, &c. &c.; and instead of its being a macule, it is nothing more than that part of the blanket which had covered the short cross of other work, and in the twelves form caused a deep and ugly impression, looking like a macule: this evil can only be remedied by new blankets, or confining the use of them to 12mo. forms.”