Blog: Enamel Dials
Date: 31 October 2018Copyright © David Boettcher 2006 - 2021 all rights reserved.
I make additions and corrections to this web site frequently, but because they are buried somewhere on one of the pages the changes are not very noticeable. I decided to create this blog section to highlight new material. Here below you will find part of one of the pages that I have recently either changed or added to significantly.
This section is from my page about Swiss marks that can be found at Dials and Hands.
If you have any questions or comments, please don't hesitate to contact me via my Contact Me page.
Sometimes enamel dials are incorrectly described as “porcelain”: this is wrong. Porcelain is made from clay and is not suitable for watch dials; it is used for tableware such as plates and bowls. Watch dials are made using vitreous enamel, which is a type of glass. In the USA this is called “porcelain enamel” which often gets wrongly shortened to “porcelain”.
The very first watch dials were metal. In the eighteenth century the process of using vitreous enamel to make high quality white, cream, or sometimes black, dials was developed.
The word “enamel” refers to any hard shiny coating such as tooth enamel, enamel paint, or even nail enamel (nail varnish). However, when used in the context of watch dials, enamel refers to an opaque or semi-transparent hard, glass like, surface applied to a metal dial plate by vitrification. Vitrification (from Latin vitreum (glass) via French vitrifier) is the transformation by melting of a substance into a glass. The full name of the substance used for watch dials is vitreous enamel.
Vitreous enamel dials have a very hard surface which is usually shiny and reflective like glass, but the surface can be made matt by rubbing with abrasive after firing.
Vitreous enamel is made from powdered glass. Tin oxide is added to make it opaque white, other chemicals are used for other colours. To make a dial the enamel is fused onto a copper dial plate by firing in an oven at high temperature, melting the glass and causing it to run together to produce a smooth glassy surface. First the overall white or black background is made, which might take four rounds of firing and smoothing to get the desired finish. Then the numbers and tracks are drawn on in black or white enamel ink, which is then also fired, at a lower temperature, to fix it to the white background.
After firing, vitreous enamel is invulnerable to ageing or fading and can be easily cleaned; an enamel dial will happily go through an ultrasonic clean. Vitreous enamel will be cracked if the dial is flexed, e.g. by being handled clumsily or levered off from the movement without releasing them first, but apart from this kind of physical damage they will last forever.
Enamel dials are expensive to make, so in the twentieth century cheaper materials were used, usually by printing the details onto a metal base and then covering with clear lacquer. Such dials are prone to discolouration, fading, and spotting, but are are extremely delicate and cannot be satisfactorily be cleaned.
Dial Cross Section (not to scale).
The cross section here shows how an enamel dial is made. A sheet of copper is cut to the correct size and shape, with holes for the hand arbors, and "dial feet" attached to its underside. Dial feet are small copper rods attached to the underside of the dial, usually by welding or soldering. They enter holes in the movement bottom plate, where they and are gripped by screws or clips. Over tightening the dial feet screws is a frequent cause of distortion to the dial plate, causing the enamel to crack.
In manufacture, the copper dial plate is coated with crushed and finely powdered glass. It is then heated in a furnace to about 800°C until the powder melts and becomes liquid, bonding to the copper and fusing together to form a coating of glass with a smooth glassy surface. This process is usually repeated several times, with the dial being cleaned and rubbed down between each layer, to get a perfectly smooth and opaque surface.
The numerals and minute and seconds tracks are then added in vitreous painting enamel, sometimes called vitreous ink, either hand painted or transferred with a stamp, and the dial is fired again. This melts the enamel of the numbers and other details and bonds them into to the base layer of enamel. In the cross section I have shown a white enamel dial with red ink on it, say a red number 12. When the enamel of the numbers and other details melts and bonds with the underlying enamel it becomes virtually flat with the dial surface as the cross section shows. The numbers and tracks become as much a part of the dial as the underlying enamel and cannot be removed.
Initially the numbers and tracks were painted by hand, but later an engraved copper block was used. The engravings were filled with vitreous ink and a gelatine pad used to pick up the ink and stamp it onto the dial. In this way many dials could be made accurately and quickly.
In the drawing of the dial cross section I have shown how enamel paint can be added to a vitreous enamel dial. Unlike the vitreous ink used to make the markings and numerals on the dial, the enamel paint cannot be fired - the paint would just burn. This means that the enamel paint does not form a strong bond with the underlying vitreous enamel, it just sits on its surface.
Enamel paint was often used to add a British retailer's name to an enamel dials of watches that were imported into Britain before the mid 1920s. Before the mid 1920s British retailers would not buy watches with a manufacturer's names or brand on their dials. If there was any name on the dial, it was that of the retailer. A small number of retailers were large and important enough to have their names or brands put onto dials in fired vitreous ink as they were made, but most did not, so enamel paint was used.
This means that Rolex, Longines, Omega, etc. watches sold in Britain before the mid 1920s didn't have their brand on the dial, and sometimes there was no name to be found anywhere. Nowadays most people expect to see a name on the dial, so some unscrupulous people have names painted on to make the watch more saleable (read "valuable"). It looks wrong.
Rolex is the most faked watch brand, so this addition of a name onto a dial in enamel paint happens most often with the Rolex name. Needless to say, just painting Rolex onto a dial does not really transform a watch into a Rolex watch. Sometimes the name is added to a genuine Rolex watch because the owner expects to see it there, but often watches that were never Rolex watches in the first place receive a new name. This is what has happened with the dial of a Marconi watch shown in the image here. If you enlarge it you can see the shiny new enamel paint on the surface of the vitreous enamel dial. It is obvious that this had been painted on quite recently.
Enamel paint is a totally different material from vitreous enamel, it is called enamel because it forms a harder, glossier, surface than other paints such as oil paint. However, enamel paint is nothing like as durable as the vitreous enamel of the dial itself. Unlike vitreous enamel, enamel paint can be easily dissolved by a solvent such as acetone or isopropyl alcohol.
Unlike the fired vitreous ink of the numerals and tracks, enamel paint doesn't bond into the underlying vitreous enamel but remains on its surface. It can usually be easily distinguished from the fired numbers and tracks by looking obliquely across the dial with a lens when it can be seen standing proud of the surface as illustrated. Because the vitreous enamel of the dial is very shiny, enamel paint has difficulty sticking to it and the added names have often become badly worn, or disappeared altogether.
If you look carefully at a vitreous enamel dial and detect that a name has been added in enamel paint, but the name doesn't show any signs of ageing, chipping or flaking, then it is quite likely that the name has been added recently.
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Names on the Dial
My grandfather's and grandmother's Rolex wristwatches. My grandfather's watch is on one of my Type B designs. Click on the picture for an enlarged view.
Throughout the nineteenth and early twentieth centuries British retailers only allowed their own names onto the dial. The concept of a "brand" being applied to watches was unknown, and the names of foreign manufacturers were simply not allowed by British retailers who, if there was to be any name on the dial, wanted it to be their own name.
Watches are often seen with the names of prominent retailers of the period such as Harrods, Asprey, Hamilton & Inches, Finnigans, etc., etc. These names are almost damaged to some degree, whereas the rest of the numbers and markings on the dial are still pristine. This is because the name was painted onto the fired vitreous enamel dial, which is very shiny so that the paint does not stick very well and bits drop off over the years.
You can see this clearly on my grandfather's and grandmother's Rolex wristwatches shown in the photograph here. Although the Rolex name is engraved onto the movements and in the case back of both watches, the dials are completely plain. These watches have been in my family since they were purchased new and have never been altered, so I know that the dials have always been plain like this.
Brand names were invented in the nineteenth century for food, to give people confidence in the purity of products. The idea soon spread to other areas, such as Kodak for film and cameras. In other countries in Europe and around the world, brand names played an important role in selling watches, but in Britain retailers stubbornly refused to entertain the idea. In the twentieth century some English watch manufacturers began to brand their watches. One of these was H. Williamson Ltd. who trademarked the name “Astral” and began to put this onto the dials of their watches around 1910.
However, this didn't meet with universal approval. Writing in the Horological Journal in 1916, Thomas Field, Managing Director, Field & Son, Ltd., Aylesbury, complained about “cheap, trashy American, Swiss and German "branded" watches” and stated “Speaking for my own firm, we have on principle never sold a "branded" watch of any description excepting those carrying the name of "Field & Son, Aylesbury."”
British retailers remained even more stubbornly resistant to the names of foreign manufacturers appearing on the dials of watches. This only began to change in the late 1920s, when Hans Wilsdorf started to advertise the Rolex brand extensively in Britain, and people started asking for Rolex watches. Wilsdorf says that when the Rolex Oyster was launched in 1927 he made the decision that he would insist that all Rolex watches carried the brand name on the dial. British retailers were suddenly faced with customers who had read about Rolex watches in the newspapers, and seen adverts for them, and started asking for Rolex watches by name. The retailers had no choice; they had to start stocking watches with the manufacturer's name and brand on them, or their rivals would and they would lose out. This was the start of a trend and other watch manufacturers soon followed.
In December 1927 the British Watch and Clockmakers' Guild held an open meeting to discuss “Pros and Cons of the Branded Article”. Hugh Rotherham kicked off the debate by saying that “in England watchmakers and jewellers insist, or most of them insist, on selling English watches with their own names on, and the public do not to-day, as a rule, look on the name as a guarantee of manufacture but as a guarantee of quality;” but noted that in Australia, New Zealand, India, Straits Settlements and South Africa, English manufactures would not sell a watch that had not got the manufacturer's name on it. A letter from the editor of the National Association of Goldsmiths Journal was read out, stating “I am afraid you will find no one in particular opposition to the branded watch except some very out-of-date retailers.” Mr. G. E. Limmer said that there was not a single watch sold in America without a brand on the dial. Mr. Charles Tucker pointed out that a branded article had to be advertised very extensively to be successful, costing between £25,000 and £30,000 a year, which was possible in America where there was an enormous market, but he questioned who would pay for this in Britain. The Secretary reported that Messrs. J. W. Benson, Ltd., of Ludgate Hill, E.C , had written to the effect that Mr. Benson was opposed on principle to selling branded articles, and that they were not sold by his firm. The meeting concluded without agreement, but the tide was clearly turning.
Watches supplied to the British market before the late 1920s usually left the factory in Switzerland with blank enamel dials. Sometimes the retailer's name was painted on in enamel paint. The importer might have offered this as part of his service to the retailer, or the retailer may have arranged himself for his name to be painted onto the dial. However, enamel paint is much less durable than the vitreous enamel of the dial itself and, in extant examples, has usually more or less fallen off. One exception to this rule are watches with Mappin „Campaign” that was fired onto the dial when it was made. But note that Mappin was a British retailer, not a Swiss watchmaker.
The advert by Baume & Co. from the Horological Journal of 1911 reproduced here is evidence of this practice. Longines watches were very highly regarded by the watch and jewellery trade in Britain, and took numerous top places in observatory competitions. But the advert says that they are supplied “without any distinctive name or mark except that of the retailer”. This is not something that Baume or Longines wanted to do. If the Longines name were put prominently onto the watches, British retailers would simply refuse to order them. Baume and Longines were immensely proud of the quality of their watches, but they were also pragmatic; they needed to 'shift product' in order to make a sales and a profit. Given the intransigence of the British retailers, they made a virtue out of necessity and made it clear that they were willing, even if they were not happy about it, to supply watches without branding.
If you have a watch dated earlier than 1930 and it has a Swiss manufacturer's name or logo on the dial, you need to be aware that this might have been added later, even quite recently, by someone trying to give the value of the watch a boost. This deception is most often found with early Rolex Watch Company items, where "Rolex" is painted onto the dials of not only actual early Rolex watches, but also the dials of Rolex's other brands such as Marconi, Unicorn, and other watches that would never have been called Rolex watches by the Rolex Watch Co. I explain why Hans Wilsdorf created brands other than Rolex at Wilsdorf's Other Brands. Before I started to expose this practice, there were few lengths that the unscrupulous would not go to. I have even seen a Marvin wristwatch from 1915/16 with Rolex laser engraved in the case back and on the barrel bridge, and Rolex painted onto the dial. Needless to say, the watch had nothing to do with Rolex.
Evidence from Longines
Mappin „Campaign” Fired Enamel
The dial shown here is from a Longines wristwatch. This dial has been through an ultrasonic clean, which is interesting because the name words Mappin and „Campaign” have not been affected. This is because the words are vitreous enamel fired into the enamel of the dial, the same as the tracks and numerals, not painted on later with enamel paint as is usually the case with British retailer's names, and which don't survive a trip through the ultrasonic tank. This, together with the opening low quote mark „ which is not used in English, shows that the name was put on in Switzerland by the dial maker as the dial was being made. Longines told me that the requirement for this dial is recorded in their archives showing that the watch left the St Imier factory in 1916 with this branding on the dial – but note, not the name Longines or the Longines logo.
Longines watches supplied to other countries at the time often, or perhaps always, had Longines fired onto the dial. From about the mid-1920s this began to be accepted in Britain. The earliest British imported Longines wristwatch that I have with a genuine Longines logo on the dial has London Assay Office import hallmarks in the case for 1928 to 1929. The Longines name is semi-circular around the top of the sub-seconds track. This of course still left the space between the 12 and the central hand boss available for a retailers name.
Fired or Painted?
How can you tell whether the name or logo was fired into the enamel, and is therefore original, or has been painted on later? Enamel paint is quite different from vitreous enamel and nothing like as durable. It is a solvent based paint applied cold with a brush, just like any other paint. Enamel paint does not stick well to glass, which is essentially what a vitreous enamel dial is made of. Names painted onto enamel dials 100 years ago have mostly flaked off partially or even completely in the intervening years.
When a retailer's name was painted onto a dial in enamel paint, by now it has partly or almost completely worn away or flaked off over the years, whereas the rest of dial markings in fired vitreous enamel are still crisp and sharp. The image of a Borgel watch here shows exactly this. The watch is an IWC in a black oxisdised steel case that was imported by Stauffer & Co. in 1908 and supplied to Hamilton & Inches in Edinburgh who retailed it. The Hamilton & Inches name and Edinburgh can still just be made out, althuogh it helps if you already have an idea of what you are looking at, but the paint has dulled to matt and mostly flaked off the otherwise pristine enamel dial. This is an easy indication that the name was painted on after the watch was made.
Hamilton & Inches painted onto Dial
When you have looked at a lot of original early twentieth century watches without a manufacturer's name or brand on the dial, seeing one immediately looks wrong and not original. However, these days people like to see a brand name so sometimes well known names are added to the dials of watches in an attempt to boost their value. A name painted on recently using enamel paint can be difficult to identify, but there are several ways in which such an addition can be identified.
- Look carefully across the dial at an oblique angle with a lens in good light. As the cross section shows, enamel paint stands up proud of the surface unlike the fired enamel numbers which are virtually flat. If you can see the name standing up like this it has definitely been added, but a very skilful painter will make the letters very flat so some painted names can be difficult to detect by this method.
- If the writing looks crisp and sharp, it is not original. Original paint has partly or almost completely worn away or flaked off over the years. It is possible that original writing has been renewed, but witout a record of what the dial looked like before this was done it is impossible to know what was there originally, if there was anything at all. If the writing makes the watch more valuable by adding the name of a famous maker that is not found anywhere else on the watch, then it is often fake.
- Wipe the suspect lettering with a solvent that dissolves paint such as acetone. Names fired into the enamel will not be affected by the solvent whereas names painted on later will dissolve and wash off, leaving the original enamel details of the dial intact.
If you have any questions or comments, please don't hesitate to to get in touch via my Contact Me page.
Copyright © David Boettcher 2006 - 2021 all rights reserved. This page updated October 2018. W3CMVS. Back to the top of the page.