Modern pigments and their vehicles : their properties and uses considered mainly from the practical side and how to make tints from them

Preface

It is to be regretted that notwithstanding it is a matter of prime importance that both dealers in painters' suppUes and users of the same — the painters and decorators — should be well posted about the materials they handle, the vast majority have but the faintest ideas concerning the properties of pigments. One would naturally suppose that dealers ought to know all about them, their values, cost of production, qualities and defects. Without such knowledge they cannot truthfully answer the questions daily put to them. This ignorance has made it possible for unscrupulous manufacturers to palm off almost anything upon them. Every manufacturer and dealer has been a law unto himself, each differing from nearly everyone else in the trade. This lack of standards was really due to the indifference caused by the lack of knowledge on the part of both dealers and consumers. It has enabled the unprincipled to fleece an unsuspecting public out of millions of dollars.

Now that the public is being made fully aware of what they buy in the way of food, and that the general government and most of the states are working together in enforcing laws which require manufacturers to state upon labels placed upon packages an exact statement of what they contain, it is to be hoped that the same protection will be extended to all other compounded material in the paint line which is subject to adulteration.

The blame for adulteration does not rest upon the shoulders of the manufacturers and dealers only. Igno-

iii iv

PREFACE ranee of what constitutes the value of an article and a desire on the part of consumers to obtain it at a cost below what it is worth are also very strong factors — possibly the main ones why goods are adulterated at all. Manufacturers and dealers would not undertake to manufacture or sell material for which there would be no demand.

The Master Painters' Association has done some excellent work in. past years to open the eyes of painters, and through its efforts in showing up the rottenness in the paint trade existing at the time of its inception a great change for the better has been brought about.

The trade journals, however, have done even more real good by bringing this work of the association to the knowledge of thousands of those painters who are not members of the association and who otherwise would never have heard of it. Thanks to this agitation which has been going on for the past eighteen years, the paint situation is in a much healthier condition to-day. Standards of quality are being established, and it is possible to obtain colors dry, ground in oil, Japan or water, which are exactly what the label represents them to be.

It is not within the scope of this little book to go into the detective business nor to make a specialty of exposing the tricks of trade. Its purpose is to give a brief and concise history of all valuable pigments useful in painting— the main sources of their derivation and supply; their properties and chief uses; their good qualities and their defects will be pointed out and incidentally there will be presented the best methods of detecting adulteration.

While tons of literature have been issued by the trade journals and in book form, very little has been written

PREFACE

V upon pigments, and most of that has been in short sketches and merely as a side issue to the main subject matter of the volumes containing them.

Some excellent books on pigments have been published in England and Germany, These were written by chemists and are of use to manufacturers in particular. They mainly treat what may be called the scientific side, the practical being only treated incidentally or ignored entirely. Of this character are such admirable works as Field's Chromatography. Its high cost, even if it treated pigments more fully from the consumer's viewpoint, would prevent its purchase by the bulk of those who otherwise would be interested in it and no doubt procure it.

It is impossible in as small a volume as this to enter into the chemistry of pigments nor into some of the intricate details of manufacture and preparations for use, except in the briefest manner that will give the reader a fair idea of its composition. This is about all that painters or dealers require to know of the chemical side of pigments. Additional details would be of no importance, and none outside a manufacturer of colors would be interested in them. This manual is written for the men who use or sell pigments and who mainly want to know what they can expect of them.

The author has made use of the best that has been said upon the subject matter in the past. He has consulted some of the best authorities and had access to nearly everything that has been published on pigments, many of these books being now out of print. He was also very fortunate in that for a few years he had the pleasure of having intercourse almost daily with the late lamented Wm. C. Wilson of Philadelphia, who at that time was probably the best posted man on pigments in America. The information thus obtained has been largely drawn upon.

vi

PREFACE

This little book will be of value to the young man who is starting out to learn the painter's trade. It will teach him what he ought to know about paints and what he will never learn from the average journeyman who is usually reticent and may very likely not know enough about pigments to answer a novice's queries. It will be useful to many painters who have never had an opportunity to study the matter of pigments, except in a haphazard sort of a way — without system and with much guess-work. As to the dealers, many of them are druggists who have a fair knowledge of chemistry. These will find the chemical details sufficient to give the information that is wanted. Other dealers not so well informed find also enough explanation to enable them to know if they are buying the right goods or paying a fair price.

It is probable that errors have crept in and will crop out when this book comes out in print. Good care has been taken that there be no glaring ones, but it is still possible that some may inadvertently have been overlooked. Be that as it may, infallibility is not claimed, but the author has given out what he honestly thinks is reliable. Such as it is, this little book is confidently submitted to an indulgent public.

F. Maire.

Hamilton, Illinois.

Aug. 30, 1907.

Chapter I Page

Preface iii

Preliminaries 1

Definition of the word " pigment." — Some substances are real pigments in water, but only so by courtesy in oil. — Synopsis of the maimer in which the subject matter is to be treated in succeeding chapters.

Chapter II

Introduction. — White lead, history, chemistry, and manufacture. — Dutch process; stack method of corrosion, cylinder method, sulphate of lead, sublimed lead. — Dahl process; properties and uses. — Blow pipe and other tests for impurities.

CHAPTER III White Pigments {Continued) 32

Zinc white; its history and chemistry, its properties and uses.

CHAPTER IV White Pigments (Continued) 40

Earth whites; their general characteristics. — Whiting (carbonate of lime) ; properties and uses. — China clay (kaolin) ; properties and uses. — Gypsum (sulphate of lime) ; properties and uses. — Silicate earths; properties and u.ses. — Silver white; properties and uses. — Baryta white (sulphate of barium) ; properties and uses.

vii viii

Chapter V Page

Ochers; history and early use made of them, methods of mining and preparing for market, divided into two classes, the silicious and aluminous, various characteristics, properties and uses of each. — Grinding colors in shops, no economy therein. — American ochers; their properties and uses. — Artificially made ochers.

CHAPTER VI Yellow Pigments {Continued) 73

The chrome yellows ; their various tones. — Medium chrome yellow, only the chromate of lead. — Canary and lemon chrome yellows. — Baryta lemon chrome yellow ; characteristics, properties and uses. — Adulterations; how to detect them. — Comparisons and the judging of values by the scale test. — Full directions for making it. — Useful for many other colors.

CHAPTER VII Yellow Pigments {Continued) 86

Gamboge; production, properties and uses. — Aureolin or cobalt yellow; properties and uses. — Indian yellow; properties and uses. — Naples yellow; production, properties and uses. — Dutch pink, yellow lake, Italian pink, quercitron, etc.; properties and uses. — Cadmium yellow; properties and uses. — King's yellow or orpiment; properties and uses.

Chapter VIII

Vermilion. — Quick silver vermilion; its history, chemistry and manufacture ; properties and uses, adulteration. — The imitation or vermilion reds ; peculiarities, properties and uses. — American vermilion ; properties and uses.

CHAPTER IX Red Pigments {Continued) 106

Venetian red; history and manufacture, characteristics, properties and uses. — Indian reds; characteristics, properties and uses. — Tuscan reds; properties and uses. — Red oxide of iron ; characteristics, properties and uses.

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CHAPTER X PAGE lift

Red Pigments {Continued.)

Red lead- its chemistry and manufacture, properties and uses — Lakes; what they are. — Alizarin and purpurin; their uses in the manufacture of lakes. — Rose pink; properties and uses —Rose lake; properties and uses. — Madder lakes; include all shades and varieties of red lakes made from alizarin and purpurin, many sold under proprietary names.— Indian lake ; properties and uses. — Carmine and the cochineal lakes; characteristics, properties and uses. — Red ochers; what they are.

Chapter XI

Chrome greens; composition, properties and uses. — All greens under proprietary names are chrome greens. — Green oxide of chromium, true chrome green ; properties and uses. — Cobalt green or zinc green; preparation, properties and uses.— Viridian; properties and uses.

CHAPTER XV Bhown Pigments Umbers. — Raw umber; characteristics, properties and uses

Burnt umber; properties and uses. — Siennas. — Raw sienna; where obtained, preparation, properties and uses. — Burnt sienna; properties and uses. — Vandyke brown; properties and uses. — The metalhc browns ; provenance, properties and uses. — Spanish brown; properties and uses.

CHAPTER XVI Black Pigments Lamp black; characteristics, manufacture, properties and uses

Carbon or gas black; properties and uses. — Ivory black.

Coach black. — Drop black. — One and the same ; preparation, properties and uses. — Charcoal black or blue black ; properties and uses. — Graphite or plumbago; properties and uses.

CHAPTER XVII Synonyms jgj

A table to facilitate the finding of pigments known under various names.

CHAPTER XVIII Vehicles used in Grinding Pigments -\nd in Applying Them 189

What vehicles are. — Raw linseed oil. — What a drying oil is.

What a fixed oil is. — The only ones of use for exposed painting.— The provenance of linseed oil; its manufacture and preparation for use. — How linseed oil dries; its properties. — Boiled linseed oil ; its properties. — Nitric acid and other tests for impurities. — Poppyseed oil; characteristics, properties and uses.

CHAPTER XIX Vehicles (Continued)

The volatile oils ; what they are ; their properties and uses in paint vehicles. — Spirits of turpentine; how obtained; its diuretic properties. — Naphtha and benzine; properties and uses. — All volatile oils solvent of gum-resins used as such in varnish making.

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CHAPTER XXIII Driers and Siccatives 229

Boiled linseed oil as a siccative; properties and uses. — The lead oxides ; the oxides of manganese. — Acetate of lead. — Sulphate of zinc. — Their action upon linseed oil and other fixed oils considered.

Chapter XXIV

Philosophy of color. — Rules to guide one in the compounding of tints.

CHAPTER XXV A List of the Principal Tints and of Pigments Required

TO Make Them 243

A few cautionary words followed by the list of tints.

MODEEN PIGMENTS AND THEIR VEHICLES : THEIR PROPERTIES AND USES

Chapter I Preliminaries

In subsequent chapters it is intended to take up a study of the various pigments which are used in ordinary painting, as well as those employed by decorators for either distemper or oil painting; those used by coach and car painters will also be reviewed. The whole field will be covered, with possibly the exception of a few pigments which have become obsolete, and which have been replaced by better ones.

The vehicles which are used in the application of pigments will also be noticed, as in some respects they are really of more importance than the pigments themselves. Binding substances and correctives will also be described, and their character and uses noted.

The word "pigment" is applied to coloring substances which, when mixed with suitable vehicles, form paints. It means "color," the word " color " being used indifferently to mean a compound of various pigments, or a pigment which has been ground ready for use; the various pigments put up in cans and found for sale at the supply stores are commonly known by that name. No matter what medium has been used in the grinding of pigments, be it Unseed oil, japan, varnish, or water, all are known as "colors" either simple or compounded. The word "pigment" is therefore much more restricted than that of "color."

Strange as it may appear, this word has not yet received its final definition. It is vaguely applied to designate any substance that may be used in the preparation of paint, fillers used in wood finishing, etc. It is given to any solid substance used in compounds, and is replacing that word in paint parlance at least.

Strictly speaking, the name of pigment should never be given to any substance unless it has the inherent power of its own to impart color to other substances with which it may be mixed. Originally it was used in this strict sense only, and it should be so restricted. As it is now, the adjunct substances possessing no coloring matter of their own which are usually added to true pigments with no other purpose in view than that of adding weight without changing the original color of the pigments in combination, are all called pigments too. It is a misnomer. Possessing no coloring matter, the makeweights are certainly not entitled to the name.

Correctives — sometimes useful adjuncts to a pigment — are frequently of the same colorless character as the makeweights, and therefore not entitled to be classed with them. To illustrate exactly what is meant, the following example is given: Starch and glue are solid substances, but after they have been converted into thin paste by the addition of hot water they are colorless, and when they have been mixed with whiting or zinc or any "colors," a distemper color has been prepared of which either may form a component part, though not as a pig-

PRELIMINARIES ment; the addition does not change the color of the compound in the least.

Here is another example: Liquid fillers, and fillers for the light hard woods, contain some transparent solid substance, such as very finely ground silex, quartz, etc.; the manufacturer in his pamphlets calls it the pigment part of the filler. He uses it in this connection actually in place of the word "solid." This is wrong, and befogs the real meaning of the word, which originally seemed admirably adapted to express the thought of coloring matter.

By courtesy some few substances will be designated as pigments that do not possess any coloring matter of their own to impart to other materials with which they are mixed. For instance, barytes has no coloring matter to impart to other pigments ground with it in oil or japan, but when used alone in water it has a white color. Several such substances which do not deserve to be classed as colors when mixed in oil, have coloring when mixed with water; and to save a double definition of them, the term "pigment," which is applicable to them when in water but which would not apply when mixed in oil, is nevertheless retained in this instance, but to which they are really no more entitled than is starch or glue. For similar reasons, carbonate of lime (whiting), sulphate of lime (gypsum) , finely powdered silicate stone or earths (silver white or English kalsomine), will also be included in the Hst of pigments, for they are properly so called when in water (if not in oil).

To facilitate the search of any particular pigment, so that they can be readily found without even taking the trouble to look them up in the index, these have been placed in groups of the principal colors, and all pigments of that tone or order will be found under the proper heading in the class to which they belong. The principal pigment, or that which is mostly used, will be placed at the head of the list, and others will follow in the order of their usefulness.

Under each will be given, as far as practicable, a brief historical sketch of its origin and derivation, its manufacture and preparation for market, its properties and uses, the best and easiest methods of detection if subject to adulteration, the enumeration of other substances which are injurious and with which it should never be combined, and, lastly, any other points of especial interest.

It was stated in the preface that it was not within the scope of this book to treat the subject matter "pigments " from the standpoint of the chemist or color-maker, and reasons were given why; but the chemistry of most all the pigment will at least be briefly noticed — simply the giving of their component parts, or, where they have a recognized formula, the giving of that. In a few of the better known ones, a full enumeration of their constituent elements will be given, as this is frequently an index as to their character; but when the desirability for this occurs, it will be done in a way that can be understood by those not familiar with chemistry, and in words as free of technical expressions as possible. A person needs not to be a chemist nor familiar with that science to understand a great deal of what constitutes the chemistry of paint; good common sense will go a long way with the reader to enable him to recognize the true from the false.

The researches and experiments made in the field of color by eminent scientists within the last 'century — many by men of the greatest ability, and who were guided more by a love of attaining knowledge than with the monetary inducements — have made the task of writing up " pigments " a comparatively easy one. The author cannot claim a great amount of originality, nor has he

PRELIMINARIES made any great discovery himself, so that what he has to say is none of his finding out, nor is it the first time that it has appeared in print. The present treatise is, in the main, one of compilation and arrangement. Nearly half a century of practical handling of pigments, and experimenting with them in paint factories and in the ordinary practice of the paint shop, have helped him form some decided opinions about the application and mixing of most pigments, and upon this fund of knowledge the writer has drawn freely and without stint, and it is embodied in this treatise with that of others.

A good knowledge of the properties of pigments is imperatively demanded of ' any one who wishes to be up in the paint business, either as a dealer or user. There is much to be learned about the proper mixing of pigments and about vehicles suitable for the various purposes: the future has a fine field for research in that direction, for we do not know it all by long odds, and there remains much to be revealed at some time or another. Much of what is known now is not of such a character that one can absolutely rely upon it; hence so many opinions which are diametrically opposed to each other about the preparation or application of the simplest of mixtures. Humiliating as it may be to one who has made a lifetime study of the paint business, the truth requires and compels one to acknowledge as much as appears above, for what now passes as orthodox in many good paint shops, will be classed as rank heresy in others of equally good repute. Therefore it is only by a thorough and intimate knowledge of pigments, vehicles, and conditions that any one can hope to grope to half-way certainty in sundry instances, and to a fuller one in a very few others. If it is so hard to get at the truth for those who are constantly studying, what must 'the practice be of those who do not study? Assuredly they can have nothing but routine and guesswork.

There is much to be learned, — all are agreed upon that. Chemists in the employ of paint manufacturers, and others who are inclined to researches in the same direction, usually make these their life hobbies; but as it is commonly on the side from their regular work, they are somewhat hampered; but every once in a while one hits upon some process or other which is beneficial and helpful in the manner of fixing the coloring matter contained in certain pigments more permanently than was ever done before, or indeed it may be the discovery of entirely new ones. Much has been done, but much still remains to be done by the chemists. On the practical side, however, there is still a great deal to be learned ; and here is work for the thinking painters, and also for the associations of master painters, who can do a great deal of good by bringing together those who, while they differ in opinions, can compare results, and thus aid in getting at true solutions of vexatious questions.

Many important discoveries of the chemists were prompted by suggestions made to them by the tests of practical men. Theoretical chemists and practical men generally cannot afford to work aloof from each other. Either one without the help of the other is more or less of a failure. Theory must be proved by practical tests to be right. Many chemists are too apt to belittle the value of suggestions made by well-posted painters, and to regard them too much in the light of useful machines for the proper application of paint. There can be little wonder that many of their compounds and discoveries of new preparations prove of no practical value. The Patent Office at Washington, D.C., is a cemetery where thousands of inventions in the paint line lie buried,

PRELIMINARIES unknown and undisturbed, simply because of their impracticability.

On the other hand, the painter too often looks at the researches of scientific men with a sneer and turns up his nose at them. All would find it advantageous to study the writings, and make use of the information they would find in them, of such men as Chevreuil, G. Field, L. E. Andes, J. Lefort, A. H. Church, and many others. Unfortunately, some of these men's works are now out of print, and are to be found only in a few of the larger public libraries.

The German language is richer with valuable scientific works on pigments than is the English, but these are very expensive, and mainly of interest to men well up in chemistry. It is hoped that translations of some of their best works may be made, adapted to the popular understanding.

Chapter II

As it was stated in the preceding chapter, to facihtate the search for any one given pigment, all have been classed into groups of certain colors, and within each will be found all which belong to it by being nearer in tone than to any other group. It is fitting to commence with the whites, as this group is the most important of all. The whites are not only important to the painter on account of its " self " color and the one self color mostly used in painting, and rightly so on account of cleanly tone and brightening effect, but also because the whites form the base upon which nearly all tints are made by the addition of colored pigments.

The ideal white pigment, is probably present to the average painter's mind, but the realization of it, as yet, has been far from the ideal one. Every practical user of paint who has given much thought to it, has some such ideal pigment mapped out in his head. He has ideas of what it should be like, — all good qualities, with none bad, — but when he goes out among the realities of life and looks, he does not find it. His ideal white pigment is to be found only in his mind. A feeble portion of the good qualities desired in a white are to be found unassociated with some very bad ones in any one white pigment. In actual practice it turns out that for every good quality shown, there will be found a counterbalancing defect which

will prove a thorn in the flesh.

The above is written for the purpose of preparing the reader for the defects which are found in all the most prominent white pigments, and also to guard him against over-confidence or extravagant expectations from the use of any.

White Lead History

White lead is the most prominent and best known of any of the white pigments on the list. There are few persons to be found, even outside of those connected with the paint trade, but who are not more or less famihar with or at least have heard of it in some way. Mankind has known white lead a long time. It is of very ancient antecedents. That the oldest civiUzations knew it, is evidenced by the remains of their pottery — the glazing upon it being obtainable only by the use of white lead. Such Latin writers as Pliny and Vitruvius give the process of its manufacture from lead and vinegar. It was then known under various names, some of which have come down to our own times, and which are used to designate it to-day. For instance, "Cerusa, minium album" in Continental Europe is still known as ceruse and white minium. Recent excavations have brought to hght a number of well-preserved specimens of white lead which show that it must have been an article of common use in ancient Greece and Egypt.

The above details are given because many people suppose white lead to be a comparatively new discovery, or at best dating back but a few centuries. It is true, however, that only a little over two hundred years have elapsed since white lead commenced to be manufactured on a large scale by what is known as the

"Dutch Process." Really, the principles of that system are the same as those described by Pliny, the only difference being that a different application of the same is made use of in the Dutch process.

While Holland has the honor of having given its name to the process that is usually employed in the manufacture of white lead to-day, that is, no doubt, due to the fact that it was in that country that were made the first efforts to manufacture it on a large scale in Europe. It had no monopoly of it, for it was not long before manufactories of it were to be found scattered in many European countries. Factories were started in Germany, France, and England not very far behind. Some of these brands of white lead soon attained a high degree of excellence, and have come down to our own times, their names being still used to designate some very fine qualities, — such as Cremnitz white, for instance, which was manufactured in the city of Crems in Germany. Not within the past hundred years has there been any white lead manufactured there, but the name still exists, the lead usually sold under that name being a flake white. So much, then, for good quality; for tradition still preserves it, and persists in handing a name down to us more than a century after the original had ceased to be made.

The Dutch Process

The "Dutch process" of corrosion has been handed down to us with but few changes from what it was in its primitive days. These changes consist only in more sensible labor-saving devices for handling the various materials used in the manufacture of white lead.

Before going into the description of the manufacture of white lead by the " Dutch process," it will be best understood if its composition be well studied; therefore the chemistry of white lead will now be given.

The component parts of white lead vary somewhat in the several specimens of it. It is sometimes erroneously called a carbonate of lead, but that it is not; at least, it is not a pure one. If it was, it would be of little value as a pigment, or rather its value would be greatly lessened. Really, it is a combination of lead carbonate and lead hydrate; the latter is what gives the saponifying and binding properties. This hydrate of lead should be present in the proportion of 30 to 35 per cent, and the carbonate should enter the combination in the proportion of 65 to 70 per cent. Lead hydrate has the property of counteracting the chalking tendency of the carbonate, but it has the drawback of rendering white lead less opaque or more transparent. White lead should therefore in round numbers have two thirds of its weight of carbonate of lead and one third of it the hydrate. Its formula is 2PbC03.

The usual process employed in the manufacture of white lead is what is known as the stack system of the so-called Dutch process, which name in reality simply stands for the chemical process producing the corrosion of the lead metal by the agency of dilute acetic acid fumes, carbonic acid, hydrogen, oxygen, and heat. The exact manner of conversion of the metal into a carbonate is very imperfectly understood even at this late day by chemists, who in their conclusions merely guess at it with more or less plausibility in their theories. It would seem that first of all it is converted into an acetate of lead, but as it has more affinity for carbonic acid than it has for the acetic, that it is transformed into that. As to the "how " and "when," this is now clouded in mystery, and it still remains for some one to satisfactorily explain.