Take some very weak isinglass size, heat it until it is warm, and then sweep the hot size over the glass. Distribute the size evenly across the glass. Then, using a gilder’s tip, apply the gold to your hair by drawing it over your hair beforehand to make the gold adhere to it. Let the extra size drip off from the glass as it’s tilted. Once it has dried, tilt the glass again and repeat this process; if you feel your gold is not sufficiently solid, you can apply another layer of gold in the same way. Finally, you may take a piece of pointed firewood, cut to the width required for the lines, and with a straight edge, draw the line that sign makers can use to rub off the gold cleanly and, thus, square and sharpen up all the lines and edges. Complete the process and then give it a coat of Brunswick black, thinned with a bit of turpentine oil, and the lines will be black. The backup paint will preserve the gold. Initially, try a small piece to ensure that everything is in order.

Early in the 20th century, the commercial potential of decorated glass became increasingly apparent. With industrialization, the market for decorative glass products and signs expanded rapidly. Dimensional signs and glass lettering incorporated the use of gold leaf around the industrialized world.

In the United States, gilded and painted glass panels were mainly used to make signs and reflected the values and tastes of an increasingly prosperous society. As fairgrounds, breweries, and railroads were at the height of their popularity during the 1920s and 1930s, sign painters used glass for decoration and advertising purposes. This extravagant style of sign-making nearly stopped altogether during Prohibition in one decade and the Depression the next. However, due to computer technology, commercial signwriting on glass has continued for generations, demonstrating various baroque practices despite, or perhaps because of, computer technology. Although the process rarely includes engraving, it does occasionally occur.

Since the end of the 1800s, more homeowners and business owners have desired gold leaf on their transoms and shop windows. Painting and gilding methods have remained almost unchanged since the Renaissance. Today, artists and sign painters apply gold leaf to glass, jewelry, picture frames, wall coverings, and panels set into furniture, such as screens and tabletops.