The Topic Is Ink
© Calvet M. Hahn 1981
A series of recent expertizing problems has made it clear that not much is known in philatelic circles, even on the expertizing committees, about writing inks and their dates, applications, and characteristics. Because ink analysis is one of the important methods of determining whether a cover is partially forged or has been tampered with, I have pulled together data on inks for my own expertizing. Some of these may have broader philatelic interest.
Old inks have characteristics that are not readily duplicated. It is difficult, therefore, for fakers to change old covers in such a fashion that it cannot be detected by experts who do have some familiarity with old inks. In looking at a cover that is under analysis, several questions need to be asked. First, is all the ink on the item the same when some should differ, and does some differ when it should be the same? For example, the address and the manuscript portion of the postmark, if any, should be in different but contemporary inks. This would not be the case, normally, if the writer is the postmaster in which case the two inks should match.
Second, do the inks used all have identical characteristics, or is one of the written portions done with ink of different quality or under different conditions? Obviously, as noted above, inks used at the postoffice and those used by the addressor at home should differ but be of generally similar characteristics.
Third, was any portion of the letter or cover written at a substantially different time? Docketing, for example, might date from a considerably later period. However, if the basic writing ink is not correct for the period of the letter than there is likely to be skullduggery a-pen. Such skullduggery is not necessarily designed to completely forge an item, although that does happen. Much more likely is that additions are made to existing covers to enhance their value. A significant date may be incorporated either in the text or docketing. Existing pen work may be 'enhanced' to make it more legible. A supplementary marking may be added.
Not too long ago, a well-known, reputable auction house offered a very rare piece of American postal history, of which about five to eight copies were known. It was shipped to me for inspection. The item itself proved to be perfectly genuine, but as the normal method of delivery was by hand, it should not have had an address-most similar examples did not. In this case, someone decided that an address would help the marketing of the piece and proceeded to add one, with no regard to the problems of the inks involved. The result was a sharp devaluation of a good item in the eyes of a serious collector. The auctioneer withdrew the piece from sale.
Not too much has been done in faking stampless covers until quite recently, unless they had good autographic content. Thus, most fakes are recent and the fakers are not familiar with the inks of the periods in question and how they are applied, as well as a number of items that can trip them up.
Before proceeding into the nature of old writing inks, it is useful to note how they were applied, both in terms of writing and blotting instruments. Obviously ballpoint pens were not used in the 19th century and the use of such writing ink is clear evidence of fakery. What may not be recognized are the differences between two of the most important writing instruments-the quill pen and the steel pen. Illustration number 1 shows the difference in writing produced by these instruments.
Note that the steel nibbed pen shows a sharp outer and inner line to the shape of the letter, whereas the same lines in the quill pen writing is almost non-existent because of the comparative softness of the quill. .
The quill pen came first, as any buff of historical movies or TV can tell us. Quill-written letters show shading in the downward strokes and there is an absence of abrasions of indentations even when the writer is a bit heavy handed. Because quills needed to be sharpened or re-cut frequently, a long letter will show differences between the writing at the end and that of the beginning. It is just about impossible to produce certain characteristics of quill writing with a steel pen, and as few of us today know how to write freely with a quill, forgery is detectable if it is tried.
Nibbed quills were invented in 1809, but their use was very rare until after the War of 1812. The development of a nibbed steel pen dates to the initial experimental example of about 1780, and the first ones were on the market about 1803. Thereafter, steel pen patents began pouring out. Nevertheless, steel pens were not in common use until the 1830s.
The early steel pens used in the United States were almost all imports from England where Birmingham specialized in their manufacture. It wasn't until about 1860 that large-scale manufacture of steel pens began in the United States. The early steel pens lacked flexibility, which shows in the writing coming from them. The reason is that it was not until 1830 that the elongated nib was incorporated into the design.
The next major development in writing instruments is the reservoir pen. The earliest of this type were the stylographic pens, which came in just about the same time that nigrosine ink was commercially available (1870). This early fountain pen version had no nib to leave nib marks. Its writing is of relatively uniform width and the strokes are comparatively broad. Shortly after the initial stylographic pens came the stub-type pen. It was rare in 1875, but grew in popularity until by 1930 about one-third of all pens were of the stub variety. See illustration 2 for a sample of how this writing looked. There is a characteristic reversal of shading from thick to thin and back again.
One of the characteristics of early fountain pens is their failure to deliver ink promptly when first applied to paper. Thus, there are frequently characteristic initial scratch marks, which indicate to an expert the use of an early fountain pen.
Although ballpoint pens were first sold prior to 1935, the first real commercial sales overseas were in 1943, and they should not be found on letters prior to that date. In fact, the use of a ball-point in American writing prior to the end of World War II-and even a few years later-makes a cover suspect. The first domestic American ballpoint sales were at Gimbels' department store in 1945.
The first ballpoint pens left a coarse structureless line with an abrupt thickness on curves, where the writing changes directions. Ballpoint writing can generally be tampered with fairly easily. About 1952, a new type of ink was introduced for these pens; that ink can identify ballpoints, and writing from pens sold after that date. This difference permits us to tell when a particular ballpoint document was written.
One problem in analyzing ink written on cover stems from the use of blotting paper. While blotting paper dates to 1465 and was used in the 1500s and 1600s, it was not commonly used. Until almost the end of the 19th century the most common practice was to let ink dry naturally in the air. If blotting was to be done, sand was used and can be found imbedded in the inks of such documents. Many covers show the effect of this sand drying either in the cancellation or in the handwriting.
It is a rare cover dating to the period prior to the War of 1812 that would show signs of having been blotted by blotting paper. Such an example would automatically call for expertization if there were any question about authenticity. Sand or air drying were the common methods right on through the prestamp period and up to about the banknote stamp era.
Iron nutgall ink, one of the most common writing inks of the 19th century, shows age discoloration much sooner when blotted than when left unblotted. It will also fade sooner, although it retains a blue color much longer, for most of the darkening agents are removed by the blotting. If the blotter is not applied immediately, only the heavily shaded portion of the writing will show this effect.
A characteristic of blotted ink that is important in expertizing is that such ink remains primarily on the surface rather than being absorbed into the paper.
Carbon inks were among the very first used. India ink is among the oldest of these, having been discovered and used about 2000 B.C. Carbon inks are made from charcoal or soot suspended in a gum, glue, or varnish medium. Because much of the best-quality ink was made from lamp black, the color varied from dark brown to blue-black.
During the 19th century, commercial carbon ink preparations were artificially darkened with a blue pigment such as Prussian Blue. The nature of the blue pigment introduced helps date India inks. Although India ink is the oldest ink in general use, it is not widely used as a writing ink. The reason is its thick nature, which is not suited for a reservoir pen. Even nibbed pens of the steel variety will clog up with this ink, unless constantly cleaned.
India and other carbon suspension inks do not penetrate paper. Rather, the layer of ink lays on the surface of the paper bound by a thin film of dried glue, with its color primarily derived from the carbon particles deposited on the surface.
Because the color comes from a layer of carbon, it is highly resistant to chemical bleaches, although it can be removed by scrubbing with a detergent. Not all the carbon particles, of course, can be eliminated, and attempts to remove carbon inks can therefore be detected by experts.
There has been a change in the composition of carbon inks over the years. Modern carbon inks are made with carbon black, not soot, and the binder is no longer hide glue but shellac in a borax solution, to which ammonia is added to promote flow. Because of the alkaline nature of carbon ink, it spreads beyond the nib marks when applied by nibbed pens.
Forgers tend to forget that carbon inks are basic in nature and therefore cannot be mixed with the acidic iron-tannin inks to darken them. Such a mixture would cause the suspended carbon to coagulate, leaving a muddy mixture.
The dating of carbon inks is primarily done by focusing on the binder and the blue toner added. Any binder, other than hide glue, indicates modern ink, particularly if there is borate present. In addition, synthetic blue agents that did not exist in the classic stamp period are used as colorants so that their presence on purportedly old covers indicates tampering.
Iron tannin inks basically replaced carbon inks in the Middle Ages as the general writing ink fluid because they were easier to handle. The large-scale use of these inks arose almost simultaneously with the introduction of paper in Western Europe . Initially, the tannin from hides was used, but it became apparent that nutgalls would serve as well so that most colonial documents use nutgall ink. There were other inks used in the colonial period, particularly during the American Revolution when improvision was the byword. These are frequently less durable and present problems in washing or cleaning covers, which the true iron nutgall inks do not. A typical and famous example is the lovely bayberry ink used at Albany, N.Y., which gives a magenta color.
The basic problem with nutgall ink is that it tales time to darken. Thus, freshly prepared inks were barely readable, an unsatisfactory situation for a writing fluid. When the ink was allowed to appropriately darken by maturing it in a vat, it was found that a large portion of the compound precipitated, creating a sludge that would clog pens. A number of items were added to prevent such precipitation and it was eventually discovered that the addition of gum Arabic hindered the formation of a precipitate although it did not prevent it. Thus, gum Arabic became a standard component of old iron nutgall inks. It gave the violet black inks a glossy look that is characteristic.
Another early change occurred when it was discovered that tannin from the tanning industry did not give the best inks, and nutgall tannin was substituted wherever possible. Nevertheless, some hide inks continued to be produced, particularly in rural areas where nutgalls were unavailable. The new nutgall inks were a combination of a solution of five percent tannin with suspension of iron salts (green vitriol) buffered with gum Arabic. The insoluble particles of blue-black ferrosoferric gallate rested on the surface of the paper while the ferrous gallate solution penetrated the paper, oxidized, and served as a mordant to create a permanent dark color.
Many of the inks produced in this fashion were quite acidic and eat into the paper as can be seen in a number of old letters. All were acidic and thus not beneficial to the paper, but some were greatly so. In 1834, a major change in iron nutgall ink technology occurred. The English firm of Stephens developed a new writing fluid that was not a part suspension but a solution. This was the first 'blue-black' writing fluid and quickly became one of the favorite inks around the world. What Stephens did was to add to his ink a small portion of indigo, and probably also some logwood. While this use of indigo had been suggested as early as 1785, Stephens was the first to do it commercially. The indigo changed the characteristic initial violet-black into a blue-black. Of course, over time (two to three years), all these inks turned into a permanent black.
The use of a Stephens type ink on a document dated before 1834 is a sure sign of forgery. This ink was not introduced in America, in all probability, for several years after that date. Through the years more and more bluing ingredients were added to these inks to create a darker initial color. Thus they took longer to turn black. Once the new coal tar dyes were commercially available for ink, they were used a colorants, so it is possible to differentiate the blue-black inks of the post 1860s from those used before, a significant point in philatelic analysis.
The next big change occurred with the study of iron gall inks by the German government in 1870. Published about 1890, the study set new formulation standards for iron gall inks, which were those subsequently used throughout the world.
Logwood also yielded tannin, and at one time logwood inks were among the most popular in use. The popularity began after Runge discovered what became known as chrome inks , which were put on the commercial market in 1848. Some of the early violet inks came from logwood. The best logwood inks were an intense blue black. They were noncorrosive and flowed freely. Once dry, they could be wetted without smearing or spreading.
Commercially, logwood inks were produced with copper or iron sulphate, with the former preferred but the latter most used. These inks used less logwood and thus were cheaper. They were acidified and thus could corrode pens. For many years such logwood inks were the standard copying ink.
Visually, matured logwood and iron gall inks look the same. However, they can be readily identified and separated by use of a 5% hydrochloric acid solution. With this, iron nutgall ink gives an immediate blue or blue green reaction while logwood yields a red or purple red color. A pipette with only a very small amount of acid can be used so that only a tiny portion of the paper is affected, or a flake of ink can be scraped away and tested.
In expertizing inks, it is necessary to recognize that logwood inks have peculiar flow that looks unlike other inks. Illustration number 3 shows how logwood ink flows back over itself when a second stroke crosses a first one. Thus at areas of shading, or where a stroke angles, there can be a flowback of the ink into other portions of the line so that it gives the appearance of retouching although it is not.