453 



AQUATINTA ENGRAVING. 



AQUATINTA ENGRAVING. 



451 



A distinction must be drawn between the constellation and the sign 

 of the Zodiac. [PRECESSION.] The latter is the part of the ecliptic 

 which begins at the horn of the constellation Capricornus and ends in 

 the middle of the body of that of Aquarius, comprising the arc of 

 longitude between 300 and 330, and forming the sun's path between 

 January 20th and February 20th. 



The following is an enumeration of the principal stars in this 

 constellation, classified according to the order of their apparent magni- 

 tudes : 



Magnitude. Number of Stars. 



3rd 3 



4th 4 



5th 18 



6th 73 



98 



Hence the number of stars in this constellation which are visible to the 

 naked eye amounts to 98. The following are the various designations 

 of the stars down to the 4th magnitude inclusive : 



No. in Catalogue 

 Character, of Flamstced. 



3 



/3 22 



y 48 



C 65 



D 62 



A. 73 



S 76 



No. in Catalogue 



of British 

 Association. 



7201 

 7478 

 7795 

 7832 

 7868 

 7970 

 7980 



Magnitude. 

 4 

 3 

 3 

 4 

 4 

 4 

 3 



AQUATINTA ENGRAVING. The word aquatinta is a compound 

 of two Latin words, aqua (water) and linrtus (stained), by which is 

 implied that this mode of engraving is an imitation of water-colour or 

 India-ink drawings. The inventor, a German artist named Le Prince, 

 was born at Metz in 1723. Although capable of very pleasing, and 

 indeed of very beautiful effects, aquatinta engraving has fallen into 

 comparative disuse : partly no doubt owing to the facility which it affords 

 for the production of inferior plates, but more to the introduction of 

 lithography. Yet, as the very facility with which it can be executed, 

 renders it especially valuable in places where skilful engravers are not 

 readily met with, and as it appears not unlikely from some of the 

 experiments of M. Ni^pce de St. Victor and others, that at least some 

 stages of the aquatinta process may be of value in heliographic (or 

 photographic) engraving, a subject likely to engage a good deal of 

 attention among amateurs, we think it may be convenient to give a 

 description of the process in sufficient detail to enable any one tolerably 

 acquainted with art to produce for himself an aquatinta engraving. 



Le Prince's method was to sift the common black resin, when tied up 

 very loosely in a muslin bag, over the plate, so as partly to cover the 

 surface with the particles. It was then fixed by a moderate heat 

 sufficient to make the dust adhere without fluxing or becoming an 

 even varnish : he thus formed a granulated surface on the plate, 

 usually called a ground, which suffered very little from the action of 

 the diluted acid, yet allowed it to corrode very freely in the small 

 spaces left between the grams of the resin. In recent methods the 

 ground is prepared by dissolving the black resin in the highest 

 rectified spirits of wine (alcohol), and then pouring the mixture over 

 the plate, the quantity of resin determining the coarseness or fineness 

 of the grain : the plate here referred to is the ordinary copper-plate 

 used by engravers, but the directions apply equally to a steel plate. 



When the ground is thoroughly dry, the surface will be of a 

 bright copper colour, and in a few hours will be ready for use. A 

 warm room is requisite for this operation in cold weather, but if not, 

 th early morning must be taken. Dust should be most carefully 

 avoided. A small plate may be held on the points of the fingers and 

 thumb of the left hand whilst the ground is laid, and be gently moved 

 about till the ground has granulated or formed ; this aids the 

 better formation or crystallisation of the grain. Before a ground is 

 laid, the plates are to be well cleansed with dry whiting and a dry 

 linen cloth, it being absolutely necessary that the plate should have 

 a very perfect polish, for without this the granulation cannot be 

 well effected. Any of the resinous gums will, with spirits of wine, 

 make a ground, but the black resin is generally preferred. Modern 

 aquatinters use a composition for painting the forms of leaves of trees, 

 or other objects, where the trouble of surrounding the forms by a 

 varnish would be too great. This composition is made of moist sugar 

 or treacle added to the same bulk of whiting', and ground well on a 

 . ith a little water ; a very email proportion of gum Arabic or 

 gamboge may be added. When this composition is used, it must be 

 thoroughly dry before the varnish is passed over it ; the varnish also 

 must be allowed time to dry, after which, cold water poured on the 

 plata will in a few minutes bring off all the composition and the 

 varnish which had passed over it, leaving the forms perfect and 

 the ground in those places free to receive the acid again the 

 remainder of the plate being permanently itopped out by the 

 varnish. This varnish is either Canada balsam or turpentine varnish 



mixed with a little lamp-black and spirits of turpentine ; with this 

 also the margin of the plate is to be varnished, leaving a narrow strip 

 of the ground for trials. These trials are made, after each time that 

 the acid has been on the plate, by taking off a small portion of the 

 strip with spirits of turpentine, cleaning the place well, and then 

 rubbing in with the finger a little powdered white lead ; this process 

 will give a good idea of the actual and comparative strengths of tints. 

 It is only by these trials that the aquatinter knows what he is doing, 

 for the acid varies so greatly with the weather, that what might be 

 considered very weak in a cool morning, becomes very strong towards 

 the evening ; for this, and other obvious reasons, if the room be kept 

 at an equal temperature, the work will advance with much greater 

 certainty than when it varies by the changes of weather. 



When the ground is dry, the design intended to be engraved is made 

 on it ; this is done in the following manner : The design is first 

 copied on very thin transparent paper, called tracing-paper ; between 

 this tracing and the prepared ground on the plate a thin sheet of 

 paper is placed, which has been rubbed over with lamp-black, or 

 vermilion, and sweet oil ; every line of the design is then gone over 

 with an instrument called a blunt point, with a moderate pressure, 

 and is thus transferred to the ground so securely that the acid cannot 

 destroy it. 



Before the acid is poured on the plate, a border or wall of wax, 

 about an inch in depth, is placed round the margin of the plate. The 

 bordering wax is made by melting together one pound of burgundy 

 pitch, half a pound of bees'-wax, and a wine-glassful of sweet oil ; 

 when melted, to be poured into cold water and worked into small 

 cakes. When wanted, these cakes are put into lukewarm water and 

 made into small rolls like a sausage, 'then flattened, and one of the 

 edges being a little melted at the fire, is to be pressed close to the 

 plate with a wet finger, making a spout at one corner ; this should be 

 well performed, or the acid will get beneath it and occasion much mis- 

 chief. In order to make the wax adhere, the plate should be made as 

 warm as the hand of the operator. 



The plate being so far made ready, the completion of the design is 

 resumed by stopping out the highest lights on the edges of clouds, 

 water, &c., with a mixture of Canada balsam or turpentine varnish, 

 and the perfectly impalpable oxide of bismuth (bismuth is preferred on 

 account of its weight) ; these are mixed with a spatula on a slab, and 

 used with a small sable brush, diluting the varnish occasionally with 

 spirits of turpentine. Next pour on the acid, which has been pre- 

 pared by mixing one-sixth of a pint of the strongest nitric acid to five- 

 sixths of a pint of water ; let it remain, according to its strength, from 

 half a minute to a minute, then pour it off, and wash the plate three or 

 four times with clean water, and dry it with a clean linen cloth or a 

 pair of bellows : the last is the best, if the stopping-out varnisk should 

 not be perfectly hard. If on trying the strip the tint is found not to 

 be sufficient, repeat the acid for another half minute, and then proceed. 

 The colour of the bismuth varnish must be changed for the second 

 stopping-out, by adding a little chrome yellow, vermilion, or lamp- 

 black, or any other colour that is not destroyed by the acid. The 

 colour is to be changed after each application of the acid, that the 

 engraver may remember in what places he has carried forward his 

 work, what tints have been softened at their edges, &c. 



It is impossible to give a scale of times for each employment of the 

 acid, but the following may serve as a guide. If the fir.-rt tint has half 

 a minute, the second may take three-quarters, the third one minute, 

 the fifth one minute and three-quarters, the sixth two minutes and a- 

 half, the seventh five minutes, the eighth twelve minutes, &c. The 

 acid should be strengthened a very little after each application ; and it 

 may be so equally done that the above proportions will serve very well 

 as a general rule, depending on the strength of the tints required. 

 When the ground changes to a gray colour it is beginning to fail, and 

 must be taken off by heating the plate till the bordering wax will lift 

 off; after this, sweet oil is applied to the whole surface, and a brisk 

 heat beneath the plate will bring off all the different varnishes with a 

 linen cloth ; then an oil-rubber, made of fine woollen cloth, rolled up 

 hard and the end cut off, applied with sweet oil, will take out the 

 stains ; tints which are too strong may be softened or even rubbed out. 

 Perhaps it need not be added, that a single grain of sand or any other 

 hard substance under the rubber will ruin the whole work. Grada- 

 tions in skies, &c., are sometimes made in this manner, though more 

 generally by pouring the acid on slowly, beginning at the darkest 

 corner. It will frequently happen that some portions of the varnishes 

 will become so hard, that the common method will not stir them ; in 

 this case a little of the oil of spike lavender applied with the finger is 

 quite certain to produce the effect. The plate is now cleaned with 

 spirits of turpentine and sent to the printer to prove, after which it is 

 to be exceedingly well cleaned with turpentine, &c., and another 

 jround laid ; this should be done in such a manner as to make the 

 jrains fall exactly on the granulations of the former ground, which is 

 called re-lriting. It is done by making the ground much stronger than 

 was used before. Fortunately, the liquid ground has a natural 

 ;endency to granulate upun the same places as before, and when the 

 acid is again applied it will act in the same interstices as before, and 

 only wants a little care to make it answer. The process for the second 

 rround is the same as for the first ; re-touching with the acid those 

 tints which require more depth, and stopping out those parts that are 



