Below I will give you what I know to be some tips on evaluating a lamp that is purported to be an antique, authentic Tiffany Studios lamp. It is not 100% infallible of course, but if even one or two of the tips prevent you from possibly purchasing a forged, fake lamp, it will be worth reading. Whenever in doubt, ask a Tiffany lamp specialist to look at the lamp for you, or only buy from a dealer, private broker, or established auction house who will give you a written guarantee of authenticity.
After you buy the lamp, I suggest showing very clear digital photos to another recognized expert for their opinion (send photos of the signature marks, and of the base and shade with light coming through the shade).
Below are things to look for on the shade first. Keep in mind these are only guidelines, although some, having to do with the signature marks, are more likely to be pretty solid clues than some of the other things. Not all lamps were made alike and not all lamps are stored over time alike. Some lamps will have much loose glass which might "rattle" and some might not.
Evaluating the Shade of an "Authentic Tiffany Studios Leaded Lamp" - Consider These Things, In No Particular Order
1. Know what shapes of shades Tiffany made. He only made a few shapes, regardless of the design. Once you know the shapes of shades he made, you can automatically rule out a shade simply because of the shade being nothing that Tiffany Studios ever produced. Click On This Link to see the shapes of the shades on my web site. A very, very few rare examples ("Cobweb," "Bat" lamp, and a few others were made), but the shapes on the above page link will cover 95% of the leaded shades commonly seen.
2. Authentic Tiffany leaded shades are going to be made of glass only. Never, ever plastic or anything else. Most of the time you can tap on a pane and tell by the sound. Also, glass shades will weigh much more than those with plastic "glass."
3. The "tap the glass" and "shake the shade" techniques: Never use these two tests to talk yourself into thinking a lamp shade is authentic Tiffany. The logic is that over time, the things used to hold the glass tight in the shade in its pattern dried out and shrank, leaving some of the glass a bit "loose."
People are told to use their knuckle to gently tap the glass panes. In theory, if you hear a rattle or the sounds of glass shifting, the shade is authentic Tiffany. It is only a possible sign that the shade is old. Obviously not all shades will be authentic Tiffany!
To make his shades, Tiffany's workers used copper foil which was created in wide sheets that were cut into thin strips that were then wrapped around the individual panes of glass. To have the inside of the foil stick to the glass, the copper was brushed with liquid beeswax before the foil was applied. It is this wax that dries out over the years, leading to the issue of the "loose panes" that sometimes rattle; not always and certainly not evidence one way or another that a shade is authentic Tiffany Studios.
Some "experts" tell you to hold the shade on each side and "shake it up and down." This is supposed to also cause one to hear glass noises of rattling or movement. Shake and tap if you wish. Depending on where you tap, how you shake, and what size and design the shade is, it could be authentic and tight without noise, or it could be a bit loose and have a "rattle. Not the most reliable test.
4. Look at the glass. Tiffany glass is known for it's vivid colors, glass surface irregularities (from ridges to fissures and lines that look like "seams") and often mottling or other things, like air bubbles and other imperfections. Other old shades can have these also, but a shade where all the glass is smooth and shiny and without any imperfections (new looking) should be suspect.
5. Some forgers actually colored the glass with types of paint instead of buying colored glass! If you wish, take a small amount of fingernail polish removal (acetone) and use a "Q-Tip" on a small area. If any color comes off, walk away! Do not put the solution on someone else's lamp without their permission, and do not put it on any metal parts.
6. Look for "hairline" or other cracks to the shade glass. It is rare (not impossible) to find a 16-25 inch authentic, old leaded glass shade without any cracks. The cracks one finds can be from hot light bulbs, from age, or from a trauma of some kind. Old cracks will usually have dirt and dust in them, making the crack stand out by being dark within the crack itself. See a photo below of cracked glass in an authentic Tiffany Studios lamp.
Evaluating the Base of a Supposed Authentic Tiffany Studios Lamp
1. Tiffany used bronze (a bronze alloy actually) on his metal bases. He rarely used anything else. On his metal base bottoms look for his stamped marks. He only used all capital letters without any "serif." It will say "TIFFANY STUDIOS NEW YORK" and occasionally "TIFFANY FURNACES NEW YORK" (without the quotes). Always all caps. Below that signature name is the model number of the base, usually a three or occasionally four digit number. These are all stamped into a bottom "plate" on the bottom of the base. While the numbers can sometimes not be exactly aligned like the letters, the tops and bottoms of the letters should all be aligned. If you see that they are in misalignment, it is a giveaway of a fake.
See authentic signatures on the base plate and on the shade inner rim edge below.
If the stamp is on the inner curve of a cone shaped shade, it can be somewhat hard to read or distorted slightly, but usually the letters still line up well. Sometimes there is also a "monogram" mark, with the initials "TGDCO" within it on base signatures. This was done when Tiffany used his decorating company as his mark. These are likewise acceptable, but you should also see the words TIFFANY STUDIOS NEW YORK. If you remove the bottom plate, (screws hold it on) you should see a gray metal ring. Most of Tiffany's bronze bases were actually hollow with a heavy ring of lead inside to make them substantial enough to to safely hold the heavy shades. If you see a base that is pot metal, zinc, brass, plastic, or wood, it is not by Tiffany Studios.
Tiffany never used onyx, plastic, ivory or anything other than occasionally authentic Tiffany glass in his bronze bases. If you see figures of people or other similar things on his bases, likewise, they would not be by Tiffany.
Other Things To Look At In Evaluating A Supposed "Authentic Tiffany Lamp"
Look at the electrical sockets. If they are original, they will have porcelain or old discolored metal liners inside. The majority of Tiffany's sockets also used hard plastic "paddle" turn knobs to turn the lights on and off. You will see a few authentic lamps with pull chains, but they are not common in his early lamps. If the sockets say "UL approved" or "Made in USA" or worse, "Made in China," be very wary. While the rest of the lamp could be authentic and have been re-wired with new sockets, it is still a "red flag." Tiffany never bought from China, and there were no "UL approved" standards or markings used during the years 1898-1928!
And always remember: Simply because you see a lovely leaded glass lamp with a bronze base that has the same floral, geometric or dragonfly pattern you have seen in books or museums, on my web site, or in a legitimate Tiffany Studios lamp gallery somewhere, it does not mean anything. Anyone with good artistic skills and the right glass and metal and other parts can create a lamp to make it look "just like" an authentic Tiffany Studios original.
The markings, the glass, some other hints above, and much experience in looking at what you know to be genuine, authentic Tiffany Studios lamps, will help you see the differences. If you are unsure, show it to an expert, get a written money back guarantee, or say goodbye to it and save your money until you know 100% certain that what you are buying is "right." Even then, as I suggested earlier, get a "guarantee of authenticity" in writing, and preferably show the lamp to an expert for their opinion while you are still within the purchase state's "statute of limitations." That way, you can either return your lamp with more authority, or if worse comes to worse, take legal action to recover your money if you made an expensive mistake.
More to come...
Dennis
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