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Authenticating oil paintings

While only one individual or institution can own an original painting, thousands of people can own a copy. Original art has been copied for centuries with reproductions providing less expensive versions for popular distribution. As a result, the world is awash in copies. Advanced copying techniques and skilled forgers can make it a challenge to distinguish a reproduction from an original piece.

There are several things to look for to determine if an oil on canvas is genuine—among them signatures, artistic styles and abilities, hand-painted versus machine-made, canvases and provenance.

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Of these, identifying the signature can be the quickest method for authentication. The question is—does the signature on the subject painting match signatures on known documents by the same artist? Fortunately, there are reference books and periodicals that contain known artist signatures for this purpose.

Another method for determining authenticity is to check the artistic style and ability. Did the artist execute the subject painting in the same style and manner as known documented paintings? Sometimes in a forgery there will be lines that are normally detailed but instead rendered in a blurry style, or the painting may use lighting techniques not normally associated with the period or artist. These are good giveaways to identifying a potential fraud.

Another tool for identifying forgeries is examining the construction of the canvas itself. An original painting may feature irregular and uneven paint on the edge of the canvas, while a print copy may have clean and even edges that can be hidden within a frame.

St. Christopher Cross the River' by Jan Wellen de Cock (Image: Thinkstock/Photos.com)

With original oil paintings, viewers can see and feel the texture of the paint and notice the colors may overlap one another. An original painting examined under a strong light might also show the pencil lines from the artist’s original sketch or changes they made while painting.

Sometimes forgers will use high quality inkjet printers to make giclée copies and then add hand-touched embellishments afterward to make them look like a real painting. On close examination, appraisers can see these copies use a dot matrix pattern similar to the ones found in magazine images. It may be necessary to use a black light to see this level of detail.

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The back of a canvas is also a great place to look for establishing authenticity. An original painting will show variations of light through the back because artists use a varying degree of impasto, or heaviness of paint in certain areas. The back of a giclée print will most likely be stark white because there are no variations in the paint technique and the paint layers.

The final important method used is the painting’s provenance—the documentation that commonly accompanies any piece of artwork confirming its authenticity. Good provenance typically leaves no doubt that a work of art is genuine. It can include a gallery label, a signed certificate of authenticity, an artist statement or recording of the artist discussing the piece, receipts, an expert appraisal, and a history of ownership including names of previous owners.

When working with provenance, it is important to establish the documents themselves are not forgeries. A reputable company will always call galleries to verify that the receipt in hand is authentic since these can be easily forged and recreated.

Certificates of authenticity should include an artist or dealer signature with a date and a thorough description of the artwork, though unscrupulous dealers have provided false COAs in the past. Also, great forms of provenance are a catalogue of an artist exhibition at a gallery or museum that displayed the artwork in question, exhibition history in general, and a reference in the artist’s catalog raisonne. Good provenance almost always increases the value and desirability of a work of art because it authenticates it with certitude.

(Image: 360b/Shutterstock)

Authenticating prints

Original prints differ from oil paintings in that they are produced on a mass scale. They are works of art created by the artist or his professional assistant from a hand-made plate, block, stone or stencil for the sole purpose of creating a limited number of images.

Because they are a different medium entirely, distinguishing authentic prints from reproduction prints requires a different set of authentication methods than oil paintings. With prints an appraiser looks to edition numbers, signatures and plate marks to make the determination.

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When an artist makes a print, it is usually produced as part of a limited number of impressions. Each print produced from the plate is technically a unique work of art even though it is produced as a signed and numbered multiple. The term for the group of prints from a single plate is called the “edition.”

This number of prints is limited to the amount that can be safely pulled from the plates before the plates begin to wear out and break down. An artist typically has control over the number of prints that can be produced from one stone and once the edition number is met, say 50 or 100, the stone is usually destroyed to enhance the value of the prints.

Original prints are numbered at the bottom with fraction numbers. The bottom half of the fraction indicates the total number of prints made. The top half of the fraction indicates which number this print occupied in sequence in the total run. So, for example, 6/100 would indicate the sixth print made in a 100-print edition.

(Image: balticboy/Thinkstock)

When examining an original print, look to the bottom of the work to find this fraction. These edition numbers can sometimes be hidden under the frame, so it may be necessary to remove the frame if the numbers are not visible.

Edition numbers are not an indication of absolute authenticity, but are an important first step. After obtaining the edition number, appraisers (and adjusters) should look to catalogs to confirm the numbers given indeed match the known number. For example, if a known edition has 200 prints within it, it should ring alarm bells if the edition number on the print states it as a number different than 200.

Prints usually have the artist’s signature on them—either done by hand after the print is done, in the lithographic plate itself, or in some case, both. If the print in question has both, it's a good sign the print is authentic. If the print only has the plate signature, it's most likely a reproduction print.

Other important things to look for when working with prints are the plate impressions and marks. Authentic prints will have a discernable plate mark where the stone pressed against the paper and this indentation should be visible around the image. Sometimes these plate marks are concealed by a frame so it may be necessary to remove the frame for proper examination.

One company recently appraised a piece believed to be a print by Picasso valued at $12,000. Using these authentication methods it was determined the piece was actually a photographic print worth no more than $100. It just goes to show that when evaluating fine art, confirming authenticity is the master piece of the work.

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Having started her career at the Cleveland Museum of Art, Erin Hollenbank, ASA, is an accredited appraiser specializing in European and American Fine Art for Enservio, a leading provider of contents claim software, payments solutions, inventory and valuation services for property insurers.