Shading Gold Leaf with Asphaltum

Try shading gold leaf with asphaltum mixed with Japan paint and thinned with turpentine.

By Jim Hingst @hingst_jim

Many of the old timers in the sign industry have used a transparent brown liquid, called asphaltum, to shade their gold leaf work. Although this oily substance smells just like tar, the two materials are definitely not the same. While tar is a by-product of the distillation of coal, one type of asphaltum, is a by-product of oil refining. Gilsonite asphaltum is another type of asphaltum, which is found in nature.

To a great extent, the transparency and ease of use of asphaltum accounts for its popularity as a glaze in the sign industry. There’s just one problem. For exterior sign applications, asphaltum just doesn’t stand the test of time. 

Exposed to extreme changes in temperature, asphaltum tends to crack.  When used to shade window lettering, over time asphaltum can also fade when subjected to ultra-violet light.   To extend its durability, some sign makers will combine asphaltum, Japan paint (such as burnt sienna or burnt umber) and a varnish (such as Spar Varnish), and then thin the mixture with turpentine.  This combination seems to greatly improve the longevity of the shading.

When using asphaltum to shade surface gilding you can brush on the glaze and then remove the excess with a lint-free cotton rag. After shading, a coating of varnish provides additional protection. For second surface gilding on glass, I have gradually built up the density of the shading, as shown in the photo above of the foliage and scroll. 

Sources for asphaltum include Angel Gilding (www.angelgilding.com), Letterhead Sign Supply (www.letterheadsignsupply.com) and Canadian SignCrafters Supply (www.signcraftersupply.com). A half pint will cost about $10.00.

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About Jim Hingst: After fourteen years as Business Development Manager at RTape, Jim Hingst retired. He was involved in many facets of the company’s business, including marketing, sales, product development and technical service.

Hingst began his career 42 years ago in the graphic arts field creating and producing advertising and promotional materials for a large test equipment manufacturer.  Working for offset printers, large format screen printers, vinyl film manufacturers, and application tape companies, his experience included estimating, production planning, purchasing and production art, as well as sales and marketing. In his capacity as a salesman, Hingst was recognized with numerous sales achievement awards.

Drawing on his experience in production and as graphics installation subcontractor, Hingst provided the industry with practical advice, publishing more than 150 articles for  publications, such as  Signs Canada, SignCraft,  Signs of the Times, Screen Printing, Sign and Digital Graphics and  Sign Builder Illustrated. He also posted more than 325 stories on his blog (hingstssignpost.blogspot.com). In 2007 Hingst’s book, Vinyl Sign Techniques, was published.

Slides of Jim's Artwork

© 2015 Jim Hingst