The method is fairly simple, aside from sampling and analysis problems. Basically it involves application of chlorophenol red with a thin brush to a page, to determine whether the pH is over 6.7, and punching out a small piece of paper, about as big as a typed capital letter, from each page found to be acid- free. The piece of paper is then tested for the presence of carbonate. In the original method, a fairly large paper sample is put into a test tube and observed with the unaided eye as 6N hydrochloric acid is poured over it, to detect effervescence. In the modified method used for this study, the tiny sample is placed on a glass dish under a microscope, the acid is dropped onto it with an eyedropper, another glass dish placed on top to get the sample into focus, and the observation made.
Effervescence indicates the presence of carbonate.
Most of the action takes place in the first two or three seconds, but it continues for 20 to 200 seconds, depending on the thickness of the paper and other factors. With a good light and a 10 or 20 power magnification, observation is not only easy but entertaining. Although this test for alkaline reserve needs to be refined in practice, it has several virtues that would allow libraries to monitor the quality of the books they buy, without having to hire chemists or destroy books in the process. Most of these 44 were commercial, not university, presses. Inc. All rights reserved.