Pittsburgh Lamp, Brass & Glass Co.: Patent and Trademark Guide

By Matthew Partsch · Owl and Twig Vintage · October 20, 2026

Four auction houses have sold a lamp from this company in the past five years. Cottone catalogued one as "Pittsburgh Lamp and Brass Co." Freeman's catalogued another as the "Pittsburgh Lamp Company." Dealers on 1stDibs write out "Pittsburgh Lamp, Brass and Glass Company" in full. None of them match, and neither do the four written histories of how the company got that name to begin with.

A company that can't agree on its own name

Pittsburgh Lamp, Brass and Glass Co. made lighting fixtures, reverse-painted lamp shades, and slag-glass table lamps out of the Pittsburgh area from roughly 1900 to 1926. Its lamps turn up regularly at auction today, usually bronze- or iron-based with a painted or marbled glass shade, in the same general style as the better-known Handel and Moe Bridges lamps of the same two decades. What doesn't turn up anywhere is a settled spelling of the maker's own name.

Cottone Auctions sold one in November 2020 catalogued as "Pittsburgh Lamp and Brass Co." — no "Glass" at all. Freeman's (now Freeman's | Hindman) sold another attributed simply to the "Pittsburgh Lamp Company." The Corning Museum of Glass's own reference FAQ calls it "Pittsburgh Lamp, Brass & Glass Company." The Early American Pattern Glass Society writes "Pittsburgh Lamp, Brass and Glass Co." Dealers on 1stDibs mix all of the above, plus a fifth version, "Pittsburgh Brass & Glass Company," that drops "Lamp" instead. Six institutions, six slightly different names, for one company that stopped operating under any of them in 1926.

The chemist who built it

The man behind the company has a clearer paper trail than the company itself. Nicholas Kopp Jr. started as a glass chemist at Hobbs, Brockunier and Company in Wheeling, West Virginia, one of the most respected glasshouses of the era. In 1890 he was hired as plant superintendent of the newly organized Fostoria Shade and Lamp Company in Fostoria, Ohio, which grew within a year into the largest glass-lamp manufacturer in the United States, employing roughly 250 people.

Kopp filed a design patent that January. U.S. Design Patent 20,566, "Design for a Closed Vessel with Perforated Cover," issued March 10, 1891, assigned to the Fostoria Shade and Lamp Company. The patent itself describes a hollow vessel shaped like a flower "of the rosaceous order," with a central neck topped by a perforated cover, made in china, glass, "or other ware" — a design history of salt shakers credits it as a shaker form. It is the only patent found in this research that carries Kopp's own name.

The Fostoria company didn't survive the Panic of 1893. Company president Charles Foster — a former Ohio governor and U.S. Treasury Secretary — filed personal bankruptcy that May, and confidence in the business collapsed with him. Pittsburgh businessmen Frank G. Wallace and Hugh W. McAfee bought the firm that November and merged it with their own company to form the Consolidated Lamp and Glass Company, headquartered in Pittsburgh, which took over operations on January 1, 1894.

Kopp stayed on through the merger. In 1894 he developed a selenium-based formula for ruby-red glass, replacing the gold compounds glassmakers had relied on for the color until then — a genuine chemistry innovation, and the achievement that made his reputation in the trade. No patent for that formula turned up in this research. Whether Kopp or Consolidated ever sought one, or simply kept the process as a trade secret the way many glass-color formulas of the period were protected, isn't something the sources checked here answer.

Kopp eventually left Consolidated and started his own company in Swissvale, Pennsylvania, outside Pittsburgh — and this is where the record splits into four different stories.

What the patent and trademark record actually shows

A federal trademark search for "Pittsburgh Lamp, Brass and Glass Co.," for "Pittsburgh Lamp," and for "Pilabrasgo" returns nothing. Pilabrasgo is not a stray dealer's shorthand — it's the company's own trade name, printed on the cover of its own 1900 sales catalog, Pilabrasgo Success Oil Lamps and Decorated Vases, catalogue number 13, 47 pages, held in library collections and catalogued by the University of Toronto. A company that put a coined word on its own catalog cover never filed that word as a federal trademark, so far as the records checked here show.

No design or utility patent assigned to "Pittsburgh Lamp, Brass and Glass Co." under any spelling turned up either. That absence is worth sitting with, because Pittsburgh-area design patents for lamp shades from exactly the same years do exist — they just belong to someone else. U.S. Design Patents 40,554, 40,556, and 40,557, all "Design for a Lamp-Shade," were filed December 24, 1909 and granted March 1, 1910, inventors Howard S. Evans and Lorin W. Young, both of Pittsburgh. A fourth, D42,046, followed in 1911, inventor William Frank M. Hawe, also of Pittsburgh. All four are assigned to the Macbeth-Evans Glass Company — a real, separate Pittsburgh glass manufacturer with no documented connection to Kopp's company beyond the city and the product category. A search engine, or a dealer working from memory, can easily credit one Pittsburgh lamp-glass maker's patent to the other.

How to tell a real one

No maker's mark on the glass itself turned up in any source checked for this guide — no embossed name, no acid-etched signature, nothing pressed into the metal base by the company itself. One documented auction lot makes the point directly: a reverse-painted lamp attributed to "Pittsburgh Lamp Company," its shade unmarked, carries a metal label on its base reading "Incandescent Supply Co." — a distributor, not the manufacturer. The attribution to Pittsburgh Lamp rests on the shade's painted scene and the base's cast form, not on anything the company itself stamped there.

In practice, attribution runs two other ways. The first is pattern-matching: the Early American Pattern Glass Society catalogs named pressed-glass patterns from the company's own line — Alba Blossoms, Beaded Drape, Golden Sunset, Prismatic, Edgewood, Petunia Swirl, and others — against which a given piece's mold pattern can be checked. Several of those pattern entries carry shorthand like "plb&g" or "pilbgco" in the society's own records; these are the society's cataloguing abbreviations, not marks found on the glass, and shouldn't be mistaken for a maker's signature.

The second is the catalog itself. Pilabrasgo Success Oil Lamps and Decorated Vases illustrates the company's own glass-stand lamps, parlour lamps, hanging library lamps, and pull-down hall lamps circa 1900–1905. Matching a lamp's shape and decoration against a surviving catalog page is slower than checking a signature, but it's the closest thing to a documented reference this company left behind.

The look-alikes

Macbeth-Evans Glass Company is the nearest and most specific confusion risk, for the reason above: a different Pittsburgh company, patenting lamp-shade designs in the same decade, with its own inventors and its own assignments, easily mixed up with Kopp's firm by anyone searching patent records by city and product rather than by company name.

More broadly, reverse-painted and slag-glass table lamps were a crowded field across the whole Midwest glass industry in the 1900s–1920s — Handel in Connecticut, Moe Bridges in Milwaukee, and a long list of smaller, often-unmarked makers all produced lamps in roughly the same painted-scenic or marbled-slag style sold through the same furniture and lighting jobbers. Without a maker's mark on the glass, a given unmarked lamp's attribution to Pittsburgh Lamp, Brass and Glass Co. specifically — as opposed to one of its contemporaries — is frequently a matter of the seller's own judgment rather than documented proof.

What they sell for

One confirmed realized price: Cottone Auctions sold a reverse- and obverse-painted table lamp, 20 inches tall with an 18-inch shade, attributed to "Pittsburgh Lamp and Brass Co.," on November 14, 2020, for a hammer price with buyer's premium of $1,800. A second closed lot — Freeman's Sale 1033, a reverse-painted lamp "attributed to Pittsburgh Lamp Company," unmarked shade, 24½ inches tall — carried a pre-sale estimate of $300 to $500, but the listing does not disclose what it actually brought.

Everything else found in researching this guide is an asking price, not a sale: 1stDibs and Etsy listings for Pittsburgh Lamp pieces run from the low hundreds into the low thousands depending on shade size and condition, but those platforms publish what a dealer wants, not what a buyer paid. Treat any number from a current listing as a starting point for negotiation, not as a market value.

Where the records disagree

Four sources were checked for this guide on how Kopp's Swissvale company became Pittsburgh Lamp, Brass and Glass Co., and no two of them tell it the same way.

The Corning Museum of Glass's own reference FAQ calls the company a "successor to Pittsburgh Brass Company, established 1898" — naming an entirely different predecessor firm than any other source checked here mentions. The trade journal Glass reports an incorporation in 1902 under New Jersey law, formed by merging "the Pittsburgh Lamp and Brass Company of Allegheny, Pa." with "the Kopp Glass and Lamp Co. of Swissvale, Pa." — plus other companies the surviving text doesn't name. The Early American Pattern Glass Society's maker record says the company "opens as Kopp Glass" in 1900 and is renamed "Pittsburgh Lamp, Brass and Glass Co." in 1901, then absorbs the Dithridge Co. in 1903. A dedicated Pittsburgh-glass history site gives a close but not identical version: Nicholas Kopp started Kopp Glass Co. in Swissvale in 1899, then reorganized with new partners in 1901 under the Pittsburgh Lamp, Brass and Glass name.

What all four agree on: a company connected to Nicholas Kopp and to Swissvale, Pennsylvania, took the Pittsburgh Lamp, Brass and Glass name somewhere around 1900–1902, and the company went bankrupt in 1926, after which it continued as Kopp Glass, Inc. — a firm the Pittsburgh Post-Gazette reported in 2018 as "founded 92 years ago," which lands on 1926 almost exactly, and which still operates in Swissvale today making technical and industrial glass. What they don't agree on is whether that 1900–1902 transition was a founding, a renaming, a reorganization, or a multi-company merger — four different words for four different legal events, from four sources that each had reason to know.

For more on companies whose own name or trademark trail doesn't match their products cleanly, see the guides to Edward Miller & Co. and Howell Co. chrome furniture. For the rest of the library, see the Field Guides index.