I N K. 



129 



Jok. 



iak. 



The preparing of printer's ink b a very delicate art, 

 and hence is in the hands only of a few. The ink used 

 in all parts of Great Britain is made in London. That 

 which is used in France is somewhat different, and 

 hence the French typography differs from the British. 

 It has a brilliancy and distinctness which we cannot imi- 

 tate, except by using the article prepared in France. 

 DiAnnce* of opinion exist as to whether these proper, 

 tie* are advantage* or not Some complain of them, as 

 mmapMiitH with a dialing effect. 



Ink used for printing from engravings by the rolling 

 preaa, mutt have less of the adhesive qualities, and a 

 UinaUr degree of yielding softness ; it must easily run 

 into, and fill the hollow lines in the copper-plate, and 

 at the same time be easily wiped off the polished sur- 

 face of the plate, previously to the taking of the impres- 

 sion. The peculiarity in the manipulation of the var- 

 nish, consists in giving it If--. t*>i1m<; than that which 

 is to be used for type ink. Lamp black is improper 

 for engraver's ink, a* it communicates to it an incon- 

 venient toughness. The charcoal blacking, such as 

 that called German, or Frankfort black, supposed to 

 l>e proem ed from burnt vine-twigs, or kernels of fruits 



.mil wine !-. i- la ins.'. r-t n |in' ili'.ii .i more trie 

 from grittmes* than the ivory black of this country. 



The preparing of engraver's ink does not require the 

 same delicacy with that of printing ink. The black, 

 indeed, require* |o be well chosen ; but when tin- i- 

 done, every engnver mixes up his own ink, which is 

 not the ease with v -r printer. 



Or cuaausnii wri- substance of a totally 



different kind, both in its colouring matter, and its 

 meMtnram. The colouring matter is a tenuious sub- 

 stance, formed by precipitating iron from a saline solu- 

 tion, by the gallic arid and tannin, and the vehicle is 

 water, slightly impregnated with a mucilage. Hut, 

 though this is the radical principle on which ink is 



But white wine formed a blacker ink than water, and vi- Ink. 

 negar formed one still blacker than wine. Spirit injured v * w *-f~ m * 

 the colour, and occasioned a precipitation of part of the 

 colouring matter. A decoction of logwood instead of 

 water, improved both the beauty and the deepness of 

 the black. A piece of iron kept in ink for a length of 

 time after it is made, improves its colour, probably by 

 uniting with the sulphuric acid disengaged by the galls. 

 In order to give ink a greater consistence, and enable 

 it better to keep the colouring matter suspended, gum 

 arabic is added, and it probably preserves the black 

 matter in a state of greater tenuity, preventing, by its 

 mechanical qualities, the attraction of cohesion from 

 forming that matter into larger particles, and thus pre- 

 fttpg it nearer a state of solution than it would other- 

 : <-. The gum also prevents it from spreading on 

 the pajier. A greater body of colour is thus collected on. 

 each stroke, and the writing retains its blackness much 

 longer than when none is added. A common addition 

 is sugar ; but its only good quality is that of communi- 

 cating a shining gloss to the writing. It renders the 

 ink more tedious in drying, and a .ufficient glossiness 

 lined by the gum alone. Dr. l.c-.vi- t'ound that 

 the addition of other metallic su! .Inch had 



been sometimes recommended, such as sulphate of 

 zinc or of copper, injured ultimately the quality of the 

 ink ; and that the galU ought to be finely powdered, and 

 not merely brui-ed, ;i- -.me had directed. 



Tin ' I )r. I-ewi-., deduced from his numerous Rtcip* of 



trials for making good ink, was one ounce of powdered Dr- Lewis, 

 sulphate of iron, one of powdered logwood, and one of 

 guin, with three of powdered galls, and a quart of white 

 . although water will serve common pur- 

 pose*. These ingredients are to be put in a glass or other 

 convenient vessel not metallic, and the mixture shaken 

 four or five times a-day. In 10 or 12 days it will be fit for 

 us*, and sooner if in a warm situation ; but it continues 



made, the pie paling of good ink require* considerable for a long time to improve if left without devastation. 



nicety in the choice of material*, a* well a* skill in the \Vhen it is separated from the powder}- residue, it will 



be kept in a good state with greater certainty, if some 

 broken galls, freed from the fine powder, and some 

 piece* of iron, are put in it. Iron, however, is the on- 

 ly metal which it is safe to retain in contact with ink. 



gall nut. It is, indeed, often improved by conjoining 



it with a little logwood It has been observed that 



many ink* are liable to become pale or to disappear. 



nipotation. Although any salt of iron would give a 

 dark precipitate. hen treated with astringent matter, 

 the only one which gives a good Mack is the sulphate, 

 and the only form of astringent which aniwers is the 



The learned and laborious Dr. Lewis instituted a se- 

 ries of minute experiment*, for the purpose of determin- 

 ing the jut proportion of the different ingredients, and 

 obtained IIBHI interesting chemical results. He found 

 that equal part* of this ialt, and of blue or Aleppo 



egave an ink which, though of a good black when 

 Bsed, became yellowuh brown when the writing 

 was kept for a moderate tunr; that in proportion to the 

 quantity of the sulphate, the ink* were less) durable in co- 



and that those in which the galls were in < 

 were most durable. Tho* it appeared that the galN w ere 

 the most perMnmg article in ink after it is applied to the 



Ti.lnr.i; art 

 therelore . 



paper, and therefore ought to be in largest proportion ; 

 that a durable ink should contain at least three parts of 

 gall- fr one of the sulphate f iron ; but when much 

 above this proportion, they render the colour '' pale. 

 The degree of dilution of ink admits of considerable 

 latitude The fullest and blackest colour i- produced, 

 when the water is ju-t sufficient to cover the powdered 

 ingredient*. But 40 or 5<> ounce* of water, toon* ounce 

 of the metallic salt, and three of gall*, make an ink suffi- 

 ciently black for common pvrpone*. ,,r rain wa- 

 ter was found, by Lewis, preJafable to common water. 



TOL, *ii. 



preiafable 



Leaden or copper vessels, when used for containing it, be- 

 come dissolved by its acid ingredients and part of the iron 

 i precipitated. Tliii fact appeared an anomaly during 

 the prevalence of the doctrines of elective affinity, a* 

 explained by Bergman. As iron precipitates other me- 

 tals from their solutions, it appeared contrary to all 

 chemical principles to suppose that these other metal* 

 were capable of precipitating iron. But, since the in- 

 vestigations of Berthollct have imparted a new, and in 

 some respects more correct, light to the doctrine* of che- 

 mical affinity, we acknowledge that the acid exert* a si- 

 multaneous attraction for both iiictaU, and dissolve* u 

 proportion of each, depending on their relative affini- 

 ties. These precautions relating to ink were clearly laid 

 down by Dr. Lewi* a* the result of practical experience, 

 while the doctrines of Berthollet were as yet unknown, 

 ami in thai state of science such precautions appeared 

 inexplicable ; but, in its present state, they are recog- 

 nised as furnishing a beautiful illustration of them. 



In order that ink may be more durable in the manu- 

 script, the paper may be advantageously dipped in a 

 solution of galls ; this obviates the fading on the back 

 of the paper; i. e. in the part to which lli ink has sunk 

 deepest, where that change i* most apt to commence. 

 1 )r I.cwii found this to be very effectual in his experi- 

 ments. Other* have recommended that the paper should 



