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PICTURE (from the Latin picture), an imitation, or representation by lines and colours of any natural object. Such representations are also called paintings, from the name of the art by which they are produced ; which, being capable of general application, and of great influence upon the mind, has, at all times, since men have cultivated their intellectual powers, been regarded with peculiar interest.

The subject of a picture may be represented in colours, on canvass, wood, or the like ; and enclosed in a frame.

Pictures or paintings in oil are preserved by coating them with sonic transparent or hard substance, as a varnish, in order to secure the colours from the injuries of the air or moisture ; and to defend the surfaces from scratches or any damages the painting might receive from slight violence. The substances that have been, or may be used for this pur pose, are gum-arabic, dissolved in water, with the addition of sugar or sugar-candy to prevent its cracking ; glair or whites of eggs, mixed with a little brandy or spirit of wine, in order to make it work more freely, and a lump of sugar to prevent its cracking ; isinglass, used as either of the tur ner, or mixed with a finirth or fifth of its weight of honey or sugar, and varnishes formed of gum resins dissolved in spirit of wine, or oil of turpentine ; which last are called oil-rarnishes.

Paintings in miniature are preserved by plates of glass, or the talc called isinglass, placed before them in the frame. Paintings in distemper may be rendered more durable, and preserved from foulness, by varnishing them with hot size, boiled to a strong consistence, in which a fifteenth or twen tieth part of honey has been dissolved. Crayons must be preserved in the same manner as paintings in water-colours, by plates of glass or isinglass.

When pictures are cut or torn, they may be repaired by laying them on an even board or table, carefully butting together the torn or divided parts with colour laid as a cement, in and over the joint, and keeping them in that situa tion till the cement is thoroughly dried. The protuberance of the cement may be easily reduced with a penknife, and the repaired part properly coloured so as to correspond with the picture. Wheu part of the cloth is destroyed, a piece of canvass, somewhat bigger than the vacant space, is to be plastered over on the outside of the cloth with white or any other colour, and when it is thoroughly dry, the inequality of the picture in this part is to be filled up with the same matter, properly reduced and coloured.

The art of cleaning pictures and paintings is of great con sequence in order to their preservation: in this operation great skill and care are requisite, so that the menstruuin used for taking off any foulness may not dissolve the oil in the painting itself; or disorder its colours, and that each sort of varnish with which paintings are coloured may be taken off without injury to the painting. The first and most general substance used for cleaning pictures is water, which will remove any foulness arising from many kinds of glutinous bodies, as sugar, honey, glue, &e., and any varnish of gum arable, glair of eggs, or isinglass, without affecting the oil that holds the colours together. Olive oil or butter will dis solve pitch, resin, and other substances of a like kind, with out injuring the oil of the painting. Pearl-ashes, dissolved in water, form a proper menstrumn for most kinds of matter that foul paintings ; but they must be very cautiously used, as they will corrode the oil of the painting, if there be no varnish of the gum resins over it. Soap is of the same nature, and should be cautiously applied, and only to par ticular spots, that elude all other methods. Spirit of wine will dissolve all the gums and gum resins, except gum arable, and is therefore very necessary for taking off from pictures varnishes composed of such substances, but it also corrodes the oil of the painting. This is also the case with oil of turpentine, and essence of lemon, spirit of lavender, and rosemary, and other essential oils. With regard to paintings that are varnished with gum-arabic, glair of eggs, or isinglass, the varnish should he taken off when they are to be cleaned. This may be easily distinguished by wetting any part of the painting, which will feel clammy, if varnished with any sub stance soluble in water. This kind of varnish may be taken off with hot water and a sponge, or by gentle rubbing with a linen cloth dipped in warm water. If paintings, on this trial, appear to be varnished with gum resins, or such sub stances as cannot be dissolved in water, they may, in some cases, be sufficiently cleaned by a sponge with warm water ; and any remaining foulness may be removed by rubbing the painting over with olive oil made warm, or with butter, which should be wiped otT' with a woollen cloth ; and if the picture require timber cleaning, wood-ashes or pearl-ashes may be used in the following manner : take an ounce of pearl-ashes, and dissolve them in a pint of water ; or take two pounds of wood-ashes, and stir them well in three quarts of water, once or twice in an hour for half a day. Then pour otr the clear fluid, and evaporate it to a quart or three pints ; wash the painting well with a sponge dipped in either of these leys, and rub gently any foul spots with a linen cloth till they disappear. If this method fail, recourse must be had, first to spirit of wine, then to oil of turpentine, and if these are ineffectual, the essence of lemons: with either of which the foul spots should be slightly moistened, and the part immediately rubbed gently with a linen cloth. After a

little rubbing, if oil of turpentine or essence of lemon has been applied, olive oil should be put upon the spot; and water. if spirit of wine has been used ; which should he taken off with a woollen cloth ; repeating the operation till the foul ness be removed. When paintings appeal' to have been var nished with those substances that will not dissolve in water. and, after the use of the above means, retain their foulness, the following method will succeed; place the picture or painting in it horizontal situation ; and moisten, or rather flood, by means of a sponge, the surface with very strong rectified spirit of wine : keep the painting thus moistened, by adding fresh quantities of the spirit, for some minutes ; then flood the whole surface copiously with cold water ; wash off the whole without rubbing ; and, when the painting is dry, repeat the operation till the whole varnish is taken off The art of removing paintings in oil from the cloth or wood on which they are originally done, and transferring them to new grounds of either kinds of substance, is of great use. For those on cloth or canvass, the method is as follows: let the decayed picture be cleansed of all grease that may be on its surftice, by rubbing it very gently with crumb of stale bread, and then wiping it with a very fine soft linen cloth. It must then be laid, with the thee downwards, on a smooth table covered with tin-paper, or the India-paper : and the cloth on the reverse must be well soaked with boiling water, spread upon it with a sponge, till it appears perfectly soft and pliable. Turn the picture with the face upwards, and, having stretched it evenly on the table, pin it down with nails at the edges. Having melted a quantity of glue and strained it through a flannel, spread part of it, when a little stiffened, on a linen cloth of the size of the painting, and when this is set and dry, lay another coat over it; when this becomes stiff, spread sonic of the glue, moderately heated, over the thee of the picture, and lay over it the linen cloth already prepared in the most even manner, and nail it down to the picture and table. Then expose the whole apparatus to the heat of the sun, in a place where it may be secured from rain, till the glue be perfectly dry and hard ; when this is the ease, remove the picture and linen cloth from the table. Turn the picture with the face downwards, and let it be stretched and nailed to the table as before ; then raise round its edge a border of wax, as in the etching of copper-plates, forming a kind of shallow trough with the surtlice of the picture ; into which pour a proper corroding fluid, as oil of vitriol, aquafortis, or spirit of salt, but the last is to be pre ferred : dilute either of these with water to such a degree, determined by previous trials, that they may destroy the threads of the original canvass or cloth of the picture, with out discolouring it. When the corroding fluid has answered this purpose, drain it off through a passage made at one end of the border of wax, and wash away the remaining part by repeatedly pouring quantities of fresh water on the cloth. The threads of the cloth must be then carefully picked out till the whole be taken away. The reverse surtlice of the painting, being thus wholly freed from the old cloth, must be well washed with water by means of a sponge, and left to dry. In the mean time prepare a new piece of canvass of the size of the painting; and having spread some hot glue, purified as before, and melted with a little brandy or spirit of wine, over the reverse of the painting, lay the new canvass evenly upon it while the glue is hot, and compress them together with thick plates of lead or flat pieces of polished marble. When the glue is set, remove these weights, let the cloth remain till the glue is become perfectly dry and hard. Then the whole must be again turned with the other side upwards, and the border of wax being replaced, the linen cloth on the face of the painting must be destroyed by means of the corroding fluid; particular care is necessary in this part of the opera tion, because the face of the painting is defended only by the coat of glue which cemented the linen cloth to it. The painting must then he freed the glue by washing it with hot water, spread and rubbed on the surflice by a sponge. The painting !nay afterwards be varnished as a new picture; and if the operation be well conducted, it will be transferred to the new cloth in a perfect state.

When the painting is originally on wood, it must first be detached from the ceiling of the wainscot where it was fixed ; and the surface of it covered with a linen cloth, cemented to it by means of glue, as already directed. A proper table being then provided, and overspread with a blanket, or thin ner woollen cloth, laid on in several doubles; the painting must be laid upon it with the face downwards, and fixed steady: and the board of wood on which it was done must be planed away, till the shell remains as thin as it can be made, without damaging the paint under it. The process is afterwards the same as that in the case of paintings on can vass, till the painting on wood be in like manner transferred to a cloth or canvass.