Highlands, UK - The Painters Magazine, a US publication of 1914, seemed more concerned about semantics than technology in its review of J Cruickshank Smith's book Paint And Painting Defects.

'… an English writer, in his little book on "Paint and Painting Defects" thinks that the terms checking and alligatoring, which he says are of American origin, are unnecessary terms, and it would be better to describe them as cracking …'

Cruickshank Smith, a Scottish paint technologist and eco-reformer, started it. In his book he wrote, '… alligatoring as applied to paint is an American term used to describe paint which resembles the markings on an alligator's back … unfortunately the same term is also used in England to describe a particular variety of wrinkling or ridging … as there is a sufficiency of English words available to describe either phenomenon it would appear to be desirable to eliminate the term alligatoring which is by no means a suggestive term to people who rarely see alligators'.

Smith's 1912 book contains page after page of written definitions of paint defects without a single line drawing or photo to illustrate them in an era when photography existed but would never have been used to record a building defect. Painters, clerks of works and architects needed to look out for work which had been 'scamped' and to accurately describe the ways in which they believed that paint, which was not the homogenous product available these days, had failed.

One of the most efficient methods of preventing the rosin in knots showing through paint, the book says, was to cover the knot with gold leaf, and in the best class of work this method was frequently adopted although sometimes the knot was bored out and filled with stopping before applying the gold leaf. The use of the words 'stop' and 'stopping' derive from the Germanic root 'stoppen' for plugging holes or gaps in planking by shipwrights. This morphed into the sense of bringing or coming to a halt from the mid-fifteenth century and the English word 'stop' has now been widely adopted in other languages.

The books states that the best knot stopping was made from button shellac in methylated spirit - a ratio of not less than 3lb to 1 gallon. It was advisable only to purchase knotting only from a house of repute and to pay reasonably high price because many samples of poor quality shellac were contaminated with rosin.

I used to make my own putty which is simple to do with linseed oil and whiting (powdered chalk). The book states that ordinary whiting is hygroscopic due to traces of caustic lime present and the best putty is made from whiting free from caustic lime and kept very dry. Wet whiting is liable to become hard or 'short; on keeping and also tends to crack after it has dried. Putty can be used as a wood filler for holes and fine cracks, which I still use and in my opinion is better than modern chemical wood fillers. If a hole or crack is too big for putty then it is better and more eco-friendly to clean it out and plug it with real wood

In 1910 J. Cruickshank Smith, who was from Aberdeenshire, wrote that 'it would be well for every practical painter to make himself acquainted with pigments of an innocuous character which can take the place of poisonous materials'.


Paint and painting defects by J. Cruickshank Smith, published by Trade Papers Publishing, London, and Painters Magazine, New York as part of The Decorator series of books edited by Arthur Seymour Jennings.