Month: February 2013

Pearls and fakes : quick identification tips

Choice examples of pearls are scarce and highly valued as gems. There are, however, a variety of other materials have been used to make faux, fake, substitute (or what other term you want to use) pearls. Fake pearls can be, amongst other things, painted over glass and plastic balls and small shells. This post offers some quick introductary tips to telling the difference between real and fake pearls, but isn’t intended to replace the opinion of a qualified gemnologist or jeweler.

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Vermeer’s Girl with a Pearl Necklace

— The most commost test for a pearl is to run it over the edge of your teeth. A real pearl will feel sandy and gritty, while fake pearls tend to feel smooth. Similarly, if you lightly rub two pearls against each other, they should feel gritty not smooth. Also, rubbing them together might produce a light powder.

If you put a pearl under a strong microscope, it looks scaly. Fake pearls often have a grainy surface.

– Closely examine the pearls for flaws. If the pearl is completely and unnaturally perfect, that points to it being a fake.

Pearls are fairly heavy and tend to be heavier than fakes. Glass, however, can have some heft to it.

If you have a string of pearls, examine it under sunlight or other bright light source. As natural pearls in a necklace were taken from different mollusks and often from different places, the tones of the pearls should differ. If the tone/color is the exact same across all the pearls, that points to them being fake.

— Similarly, under black light the different pearls should fluoresce differently on a string of pearls, and will tend to fluoresce yellowish or tan. Fake pearls will tend to be uniform across the line.

— As wild pearls were made in nature, they rarely to never are perfectly round. If pearls on a necklace are perfectly round, that points to them being fake.

Cultured (rather than natural or wild) pearls were introduced in the 1900s. If there is rock solid provenance showing a pearl or pearls is from before 1900 is significant.

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An aid in identifying materials: the Mohs scale of hardness

the ruby has a Mohs hardness of 9

the ruby has a Mohs hardness of 9

The Mohs scale of hardness is used to identify the relative hardness of a substance, from copper to glass to alabaster.  The scale based on the ability of a harder substance to scratch a softer.  Diamond is able to scratch steel, steel is able to scratch wood, wood is able to scratch chalk.  In the Mohs scale materials are assigned a level of hardness 1 through 10, with one being the softest material (talc) and 10 being the hardest (diamond).  If a material has a Mohs hardness of 5, that would means it would scratch a material with a hardness of 3.  If an as advertised as diamond (supposed to have a hardness 10) is scratched by steel (hardness 5), then it clearly is a fake.  And you’ve probably seen this diamond test done before in movies.
Along with other tests and observations (color, shine, weight, etc), the Mohs test is often used to identify a material and weed out imposters.

You can buy inexpensive Mohs testing kits on eBay and at amazon.  The kits simply contain 9 different minerals with a mohs hardness of 1 through 9.

penny

Mohs hardness of 3

You can also use many around the house items for quick reference, including glass, nails and pennies.
The following is a 1 through 10 list of different substances..

1 (softest): tacum, chalk
1.5: tin, lead, graphite
2: gypsum, plaster of paris
2.5-3: human fingernail, magnesium, gold, silver, aluminium, zinc, Jet (lignite)
3: calcite, US penny, copper, arsenic, antimony, thorium, dentin
4: fluroite, iron, nickel, iron nail
5: apatite, tooth enamel, volcanic glass
5.5-6.5: window glass
6:  titanium
7: quartz, steel file, ceramic tile
7.5-9: emerald, hardened steel, tungsten, garnet
8: topaz, cubic zirconiam
9: corundom, ruby
10 (hardest): Diamond

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Identifying and dating paper

George Washington letter

George Washington letter

Having a basic knowledge of paper is important for collectors and dealers. Many fakes and reprints are identified as the paper is too modern or the wrong type for the print to be an original. This following a brief look at some important types of paper throughout history.

While the type and age of the paper can help determine the authenticity of a print, it is not in and of itself proof. Some forgers use old paper. However, many prints, collectibles and documents are identified as fakes because the paper used is too modern or otherwise inconsistent with the original. It is also often known exactly what kind, even brand, of paper famous artists used for their valuable prints.

For a specific original Picasso print, it is often known exactly what kind of paper, and even watermark, he used.

For an original Picasso print, it is often known exactly what kind and brand of paper, and even watermark, he used. Thus, many fakes are easily identified.

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The following are standard types of paper.

Laid paper: Until the 1750s, all paper was laid paper. It was made on a mesh consisting of strong wires about an inch apart, with finer wires laid close together across them. This gridiron pattern can be seen when the paper is held to the light. Today, some writing paper is still laid, though the pattern being more of a decoration.

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closeup of old laid paper with the gridiron pattern and watermark

A paper print from the 1500s or 1600s has to be on laid paper.

Wove paper: About 1755, wove paper was invented. Wove paper is made on a finely woven mesh, so the paper does not have the rigid lines pattern of laid paper. Laid and wove paper are easily differentiated when held to the light. Most of today’s paper, including computer printer and typing paper, is wove. No print from before 1750 could be on wove paper.

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laid paper (left) next to wove paper

Rag versus wood pulp. In the early history paper was made from rags. Starting about the mid 1800s, rag pulp began to be replaced by wood pulp. Wood became a popular choice due to the scarcity of rags and because wood pulp paper was cheaper to manufacture.The first successfully made American wood pulp paper was manufactured in Buffalo, New York, in 1855. By 1860, a large percentage of the total paper produced in the U.S. was still rag paper. Most of the newspapers printed in the U.S. during the Civil War period survived because they were essentially acid-free 100% rag paper, but the newspapers printed in the late 1880s turn brown because of the high acid content of the wood pulp paper. In 1882, the sulfite wood pulp process, that is still in use today, was developed on a commercial scale and most of the high acid content paper was used thereafter in newspapers, magazines and books.

Counterintuitively, modern paper, especially in books, letters and newspapers, is much more likely to turn brown and brittle than paper from before the American Civil War. For the beginning collector, the paper on an early 1800s print can be surprisingly fresh and white.

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It’s the wood pulp in 20th century newspapers that makes them turn brown

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Chronology of Paper

The following is a brief chronology of paper history.Paper has been traced to about

105 AD China.It reached Central Asia by 751 and Baghdad by 793, and by the 14th century there were paper mills in several parts of Europe.

105: Paper making invented in China.


400: Invention of true ink in China.


610: Papermaking introduced to Japan from China.


770: The earliest instance of text printing upon paper, in China.


868: Earliest printed book, the Diamond Sutra, in China.


900: First use of paper in Egypt.


1228: First use of paper in Germany.


1282: Watermarks first used in Europe.


1319: Earliest use of paper money in Japan. 


1450-55 Johan Gutenberg’s forty two line Bible produced.


1470: First paper poster, in the form of a bookseller’s advertisement.


1521: First use of rice straw in Chinese paper.


1589-91 European printing introduced to China and Japan.


1609: First newspaper with regular dates (Germany)


1662: First English newspaper introduced


1869: The first ‘Dutch Gilt’ papers made in Germany.


1750: Cloth backed papers introduced.Used for maps, charts, etc.


1755: Wove paper introduced


1758: First forgery of bank notes


1763: First Bible printed in American using American paper.
1800-10s: Practical paper making machines developed


1824: First machine for pasting sheets of paper together is introduced.Cardboard is first formed.


1830: Sandpaper introduced commercially.


1830s: Coated paper introduced. This paper is usually coated with China clay, which makes it white and smooth, sometimes glossy.It is most often used in art and illustrated books.


1842: Christmas card invented.


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The first commercially produced Christmas card.

1844:First commercial paper boxes made in America.


1854:Paper made from chemical wood pulp patented.


1862:Tracing paper introduced commercially


1871:Roll toilet paper introduced.


1875:First instance in U.S. of paper coated on both sides.


1903: Corrugated cardboard introduced.Replaced many wooden boxes.


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corrugated cardboard

1905: Glassine paper introduced


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translucent glassine envelopes are used to hold stamps, greeting cards, etc

1906: Paper milk-bottles introduced


1909: Kraft paper introduced


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kraft paper bag

1910: Bread and fruit wrapped in printed paper

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Some common fine art paper terms

Blind stamp: an embossed sealed used to identify the artist, publisher, printer or collector.


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blind stamp

China Paper: a soft paper made in China from bamboo fiber.


Chine appliqué,or chine collé: A chine appliqué isprint in which the image is pressed intoa thin sheet of China paper which is backed by a thicker and stronger paper. Some proof prints are chine appliqués.


Cold pressed: A paper with slight surface texture made by pressing the finished paper between cold cylinders.In between rough and hot pressed papers.


Deckle edge: the rough, almost feathery edge on hand made paper.


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paper with deckle edges

Drystamp: blindstamp.


Embossment:A physically raised or depressed design in the paper.


Enameled paper: any coated paper.

Glassine paper: A super smooth, semi-transparent paper that is often used to make the envelopes that hold stamps


Hand made Paper: Paper made by hand in individual sheets.


Hot Pressed: A paper surface that is smooth.Made by pressing a finished paper sheet through hot cylinders. 


India paper: an extremely thin paper used primarily in long books to reduce the bulk.


Machine Made Paper: Made on a machine called a “Fourdrinier.”Produces consistant shape and textured paper.


Marbling: a decorative technique of making patterns on paper


Mouldmade Paper: paper that simulates hand made paper, but is made by a machine.


Parchment: An ancient form of paper made out of animal skin.It is smooth and semi-translucent


Plate Finish: A smooth surface made by a calendar machine. 


Rag Paper: Made from non-wood fibers, including rags, cotton linters, cotton or linen pulp.


Rough: a heavily textured paper surface


Tooth: A slight surface texture.


Vellum: a modern version of parchment, with the same dense, animal skin-like appearance.A slightly rough surface and is semi-translucent.Some drafting paper is called vellum. 


Velox: Black and white paper print for proofing or display.

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Watermarks

For centuries paper manufacturers have often distinguished their product by means of watermarks.A watermark is a design in paper made by creating a variation in the paper thickness during manufacture.The watermark is visible when the paper is held up to a light.Watermarks can sometimes give important information about the age of the paper and the authenticity of the print.

Watermarks are known to have existed in Italy before the end of the 13th century. Two types of watermark have been produced. The more common type, which produces a translucent design when held up to a light, is produced by a wire design laid over and sewn onto the sheet mold wire (for hand made paper) or attached to the “dandy roll” (for machine-made paper). The rarer “shaded” watermark is produced by a depression in the sheet mold wire, which results in a greater density of fibers–hence, a shaded, or darker, design when held up to a light. Watermarks are often used commercially to identify the manufacturer or the grade of paper. They have also been used to detect and prevent counterfeiting and forgery.

rarer shaded watermark on a Malaysian bank note

rarer shaded watermark on a Malaysian bank note

Catalogues raisonne often list watermarks used or otherwise discuss watermarks as it relates to the artists’ work.

Examples of how watermarks help identify prints:

If a Salvador Dali print has a watermark consisting of the word “ARCHES” with an infinity sign (sideways ‘8’) beneath, the print is a fake. Dali used ARCHES brand paper, but in 1980 ARCHES added the infinity sign to the watermark. 1980 was past Dali’s working career and Dali himself stated that he never used the ‘infinity’ paper. While this watermark is easily identified, some enterprising forgers and dealers, picked the ‘infinity’ paper where the watermark was near an edge so they could conveniently cut off the infinity.A simple rule of thumb for collectors, is to make sure that you buy a Dali print on Aches paper where the watermark is entirely on the paper and away from an edge.

For John James Audubon’s large size “Birds of America” prints, the presence of a “J. Whatman” watermark is strong evidence that the print is original. No known reprints or later restrikes are on paper with that watermark.

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1835 J Whatman watermark on an Audubon print

Pablo Picasso sometimes used paper with his personal watermark

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Using black light to identify modern paper

A black light is effective in identifying many, though not all, modern paper stocks. This allows the collector and dealer to identify modern reprints and fakes of antique trading cards, posters, photographs, programs and other paper memorabilia. Many people buy a black light specifically for this purpose.

Many antique paperstock collectibles are identified as fakes simply by shining a black light on them

Many antique paperstock collectibles are identified as fakes simply by shining a black light on them

Starting in the late 1940s, manufacturers of many products began adding optical brighteners and other new chemicals to their products. Optical brighteners are invisible dyes that fluoresce brightly under ultraviolet light. They were used to make products appear brighter in normal daylight, which contains some ultraviolet light. Optical brighteners were added to laundry detergent and clothes to help drown out stains and to give the often advertised `whiter than white whites.’ Optical brighteners were added to plastic toys to makes them brighter and more colorful. Paper manufacturers joined the act as well, adding optical brighteners to many, though not all of their white papers stocks.

A black light can identify many trading cards, posters, photos and other paper items that contain optical brighteners. In a dark room and under black light optical brighteners will usually fluoresce a very bright light blue or bright white. To find out what this looks like shine a recently made white trading card, snapshot or most types of today’s printing paper under a black light. If paper stock fluoresces very bright as just described, it almost certainly was made after the mid 1940s. It is important to note that not all modern papers will fluoresce this way as optical brighteners are not added to all modern paper. For example, many modern wirephotos have no optical brighteners. This means that if a paper doesn’t fluoresce brightly this does not mean it is necessarily old. However, with few exceptions, if a paper object fluoresces very brightly, it is modern.

smaller 1930s photo on top of a 2000 photo, showing the difference in fluorescence under black light

smaller 1930s photo on top of a 2000 photo, showing the difference in fluorescence under black light

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Ivory, bone and fake ivory

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Purchase a copy of Identifying Common Materials in Antiques: A Pocket Guide

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Ivory is a traditional and valuable material that comes from from the tusks or tooths of elephants, hippopotamus, narwal whales, wild boars a a few other animals. Since ancient times, ivory has been used to make figures, buttons, combs, chess boards and more.   

Genuine ivory has long been a challenge to identify, as similar looking items have been made out of bone, vintage plastics, ceramics and nuts. The following is a quick look at telling the difference between ivory and it’s fake counterparts.  

Ivory.  Ivory is heavy and cold to the touch when you put it to your cheek.  It will usually have ” Schreger lines.”  These lines may be cross hatching or in circular rings. If you do the so called ‘hot needle’ test and press the tip of a hot needle to ivory surface, it will not press in and may slightly smell of bone.

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Shreger lines in ivory

Bone.  Bone will not have the Schreger lines, but will have brown or black pores.  The brown or black is from the accumulation of dirt.  If you press a hot needle to it, it may smoke and will smell of bone.

Plastic ivory.  The most common antique plastic versions of ivory are from bakelite and celluloid.  Bakelite can be heavy like genuine ivory, but celluloid is noticeably light and translucent.  If you press a hot needle to the plastics it will press in easily and smell like chemicals rather than bone.  For a less destructive test test, you can put the item under hot water and get the same chemical smell.  French ivory and ivoryide are names for celluloid ivory.

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Celluloid ivory is thin and was often used to make combs, brush handles and mirror frames.

Vegetable ivory.  Vegetable ivory is carved from a very hard Tagua nut of South America, and was commonly used to make little figures and buttons.  It will have a pattern similar to Shreger lines.  The husk of the nut is dark brown and often is part of the carving.    The hot needle test will produce the smell of burning walnut shells.

Rabbit-sm

vegetable ivory carving with the nut’s brown husk remnants on the bottom

Victorian scraps

ImageA popular hobby in the 1800s was collecting ‘scraps.’ Scraps were small factory manufactured paper pieces depicting most every popular subject from cute animals to royalty, soldiers to flowers. They were nicknamed scraps because they resembled scraps of paper. They were sold to collectors in uncut sheets. With early sheets, the individual scraps had to be cut out by hand. The pieces in the later sheets came factory die cut. The later versions were brightly colored and detailed and often embossed.

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1800s album page with various die cut scraps pasted on.

1800s album page with various die cut scraps pasted on.

“How can you tell the difference between a real 1950s Red Man baseball card poster and a reprint?”

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cardboard reprint of 1953 Red Man poster featuring Johnny Mize

The original posters were on thin poster paper and in person have strikingly high quality graphics– crisp, colorful and bright. I have heard that most of the reprints are on cardboard. There was a find of unused original posters, so the originals can be found in strong condition.