White lead

“ Their usual Whites are either artificial or natural White Lead, the last of which is the best they yet have, and with the mixing and tempering these colours together, are they able to make an imitation of any colour whatsoever: Their Reds or deep Yellows, they can dilute by mixing pale Yellows with them, and deepen their pale by mixing deeper with them; for it is not with Opacous colours as it is with transparent, where by adding more Yellow to yellow, it is deepned, but in opacous diluted. ”

“ Numerous substitutes have been introduced during the past two decades, but white lead still retains its pre-eminent popularity. Lead compounds and various adulterated brands have given the painter plenty of trouble, and caused him to devote more attention to the quality of his white lead stock than formerly. Because of its soft, pliable, grain-filling property, its established elasticity, density, body, fine working quality, and its merits as a reliable drying pigment, white lead is the filling up and foundation material par excellence. ”

“ We may sum up the whole matter as regards white lead making by the stack or Dutch method in a few brief words: It is a most tedious and uncertain operation; it is a most dangerous occupation for all concerned; it is founded upon no true principles of any kind; and of science its whole course is ignorant. White lead making is ruled by a “happy-go-lucky” philosophy. The representatives of this manufacture are completely ignorant of the scientific details relating to it, and hence we may not be surprised to find amongst them an enormous amount of ignorance and prejudice. ”

“ White lead is the most valuable of all the colouring bodies, since it enters into the composition of almost every other. It is made by exposing sheet-lead to the action of vinegar, by which a white substance is procured. ”

“ In this sort of work it must be remembered that it is the white lead we depend upon, and the other material which we use—the tin and the rags—are only for the purpose of protecting and holding the white lead in place. ”

“ White, in Christian art represented by the diamond or silver, was the emblem of light, religious purity, innocence, virginity, faith, joy, and life. (J.)
White is in theory the result of the union of the three primary colours. The principal white pigments are white lead, Lake white, Krems white, zinc white, constant white (q.v.) . (See Carbonate of Lead, Oxide of Zinc, &c.)
White Copper. German silver.
White Lead is the white pigment universally used for oil painting; it is considered a good dryer, and is used to render oil more drying. ”

“ White lead is an amorphous white substance which, when mixed with oil, has great covering power, that is, it spreads out in an even waxy film, free from streaks and lumps, and covers the entire surface upon which it is spread. Its disadvantage as a pigment lies in the fact that it gradually blackens when exposed to sulphur compounds, which are often present in the air, forming black lead sulphide (PbS) . ”

“ If two different white leads ground in oil to an equal consistency are applied to different panels of a door, primed in the same manner, the one of the two leads that possesses the better body will be shown by it hiding the grain of the wood better. Some white leads, especially those that are manufactured by the new processes, lack this important quality of body, and three coats will only cover the work as well as about two of old process white lead. ”

“ Good white lead is a dense, perfectly amorphous powder of perfect whiteness, possessed of great body and covering power when combined with oil. When mixed with linseed oil and used as paint it rapidly dries in the air and assumes a varnish-like, glossy, hard surface, and is capable when once dry of resisting the action of air and water for any length of time. It does not weep when laid on a surface with a brush, that is, the oil does not separate from the solid material of the paint. ”

“ To sophisticate white lead, and produce the various inferiors named, dry powdered white lead is needed as a starting point, and for this purpose principally arises the necessity for its production. If ground in oil the adulterants cannot be properly incorporated with it. Dry white lead is used for nothing else that could ever give rise to any great demand for it. ”

“ These are mixed with the white lead, and then the mixture is ground with oil and formed into paint, sold under various names according to quality: thus—guaranteed white lead, firsts, seconds, thirds, and fourths, the proportion of white lead diminishing, and that of the adulterant increasing, as we descend from the pure material. Guaranteed and best white lead is not pure, and does not mean pure white lead. Pure white lead can be purchased at some makers, but its price, if pure, can never fall below 19l. ”

“ To Determine The Covering Power Of Pigments.—To determine the covering power of white lead, or any other pigment, take equal quantities of several varieties of white lead and mix them with a darker pigment, black, blue, etc., the latter also in equal proportions. The white lead which retains the lightest color is naturally the most opaque. In a similar manner, on the other hand, the mixing power of the dark pigments can be ascertained. ”

“ Many painters look upon paint as necessarily consisting of white lead to which has been added sufficient colouring matter to give the desired tint. As a matter of fact, white lead may be wholly absent from a paint. For example, yellow ochre may be used by itself; iron oxide in the shape of Indian red, purple brown, Venetian red, or Tuscan red forms in itself a good paint if the colour is not objectionable. Again, in the lighter paints we sometimes have white lead replaced by an admixture of zinc white, barytes and other materials of the kind. ”

“ White lead makers, recognising this peculiar incrustation as the only one capable of fulfilling their desired purpose of making good white lead paint, do not even recognise any other as of any service for that purpose, be it good or bad. ”

“ Now, whereas it may here again be objected, that neither can the Reds be made out of the Yellows, added together, or laid on in greater or less quantity, nor can the Yellows be made out of the Reds though laid never so thin; and as for the addition of White or Black, they do nothing but either whiten or darken the colours to which they are added, and not at all make them of any other kind of colour: as for instance, Vermilion, by being temper'd with White Lead, does not at all grow more Yellow, but onely there is made a whiter kind of Red. ”

“ Briefly, white lead is valuable because it possesses better “body”—i.e., the property of covering or hiding the surface to which it is applied—than any other pigment. Its poisonous character is against it, as is also the fact that it is affected by certain gases. Zinc is an excellent pigment; it is whiter than white lead, but is somewhat deficient in body. Lithopone and Charlton white are both excellent substitutes for lead, and are non-poisonous.
[22]
CHAPTER IV.
Grays and Greys. ”

“ For the black-veined variety the white lead ground is gone over here and there, but not too much of it, with a touch of black which must be vigorously worked into the white to produce a few blotches of light, faint gray not prominent at all. The veining is gray of a trifle darker tone, which is called black by courtesy and as a contrast to the white of the ground. ”

“ If experiments are made with a variety of white lead or zinc white, by the admixture of dark pigments, the color which tints the white lead or zinc white most, also possesses the greatest covering or mixing power. ”

“ It is the white lead of commerce; but what is familiarly called white lead, is this substance ground up with linseed oil into a thick paste so as to be ready for the use of painters.
White lead is a very poisonous substance, and produces the disease called painters’ colic, when taken into the system in minute quantities and for a long time, so that all who have much to do with this dangerous substance, as house-painters and artists, should be extremely careful that their hands are well washed frequently, and especially before going to meals. ”

“ Substitutes for white lead of a non-poisonous nature, or of such a nature as not to produce such deadly effects in their preparation or use as white lead does, have been proposed; their introduction has not, however, been a great success. A mixture of sulphate, sulphide and oxide of zinc is a patent white made by subliming galena in an oxidising furnace or hearth. This compound lacks body.
All of these so-called substitutes are very inferior to white lead, not only as to quality but as to cost. They cannot compete with white lead. ”

“ Five parts of white lead mixed with two parts of carmine give a rose colour that is suitable for inside work only. An admirable rose colour may be obtained by using zinc white instead of white lead, as the zinc is a much purer white than the lead, and hence gives a purer tint. ”

“ Persons go on year after year laying out sums of money for having their houses painted with white lead, when other pigments which will keep their colour might well be employed. A house painted with white lead after some time darkens in tint considerably; the colour is changed by some influence that is acting upon it through the air, and that influence is sulphuretted hydrogen gas. ”

“ In order to satisfy this demand, the only course open to the colour-maker is to mix the white lead with a120 cheap white substance, which enables him to turn out different grades of white lead, which, although low in price, are far inferior to the pure article in covering power. Pure white lead being itself a very heavy substance, the only bodies suitable as adjuncts are such as are also of high specific gravity; and of all the cheap pigments known, heavy spar is the only one endowed with this property. ”

“ White lead is now very seldom sold in the dry state, but samples are occasionally met with. Its covering power being superior to that of any other known paint, it is very largely used, and it is frequently adulterated with substances of inferior quality. ”

“ Attempts have been made to produce white lead quickly and cheaply by precipitating processes, but in all such methods the resulting compound is deficient in certain special qualities absolutely necessary to white lead proper and to its uses. The precipitated white lead is always of a crystalline structure, and crystalline lead can never furnish a good body paint—no amount of pulverising and grinding of this crystalline material will correct this defect in its nature, and deprive it of its crystalline form. ”

“ In order to obtain a cheaper product, white lead is frequently mixed with barytes which is distinguished by its white color and great specific gravity. The mixture is often effected in fixed proportions and for certain varieties of white lead, which are known by special names or numbers, remains unchanged. ”

“ Now, this striking through is owing to a slight process of saponification, no doubt owing to an interchange between the carbonic acid of the lead carbonate and the stearic and oleic acids of the oil with which the lead is mixed; so that, in time, the white lead, which has a body which makes it so great a favourite with artists, loses that body, and becomes a transparent or semi-transparent substance, something like lead plaster. Here is a reason why white lead should not be used unless the ground has previously been brought to a light colour. ”

“ A red color has sometimes been observed in white lead, and has been formerly attributed to the presence of silver. German investigations have recently shown that this is incorrect, and that the red tinge is due to defects in manufacture. ”

“ Many painters get excellent results by using white lead for the under coats and zinc white for the final coats.
Commercial White. Seventeen parts of white lead, three parts of barytes. This is intended to be mixed in oil, not water.
Permanent White. The best quality barytes or blanc fixe makes a permanent white when ground in water. In oil it lacks body. For many purposes a white which will last a considerable length of time is made by mixing two parts of zinc white with one part of barytes.
YELLOWS.
If a yellow is too bright it may be lowered by adding a small quantity of blue and red. ”

“ When the colour of the best grades of chalk are compared with what may be termed pure white—such as that of white lead, zinc white, permanent white—a skilled eye will always detect a greyish or yellowish tinge in the former, even if obtained from the whitest Carrara marble. ”

“ A good shade is obtained by mixing eight parts of white lead, two parts of French yellow ochre and a touch of Venetian red. French ochre and lead alone are often employed. Equal parts of raw sienna and orange chrome used to tint white gives a nice cream. ”

“ The chrome yellows, chrome greens, and Prussian blues are fugitive, whether used alone or mixed. A combination of two colors of durable nature is often subject to change of tone. Of the more durable colors for external use, the ochres, Indian and Venetian reds, burnt and raw umbers, and burnt and raw siennas may be mentioned. Zinc white, though of less body than white lead, is more delicate and durable, and should always be used in place of white lead at the seashore, where it is especially durable. The action of the salt air injures the lead. ”

“ Greek green you will temper with acid, deepen with black, and heighten with white, made from stag's horn (ivory black) . Mix green with white lead, deepen with pure green, and heighten with white lead. Greenish blue, deepen with green, heighten with white lead. Yellow, deepen with vermilion, heighten with white lead. Indigo, deepen with black, heighten with azure. Item, mix indigo with white, deepen with azure, heighten with white lead. Brown, deepen with black, heighten with red lead. ”