To the Editor:
Those who attended Tim Barrett's demonstration at the 1981 AIC conference in Philadelphia may wish to add the following new information to the paper samples and data sheets that were handed out:
| Paper Case Paper | ||
|
Prototype |
Kozo Tissue | |
| pH of cold water extract: | ||
|
blank | 7.60 | 7.60 |
|
sample | 8.60 | 8.90 |
| Calcium (%) | .9 | 1.8 |
| Copper, ppm | 7.7 | 3.4 |
| Iron, ppm | 46.4 | 32.9 |
| Manganese, ppm | 3.1 | 15.5 |
| Sodium, ppm | 30.9 | 16.8 |
| Magnesium, ppm | 176.2 | 1307.1 |
| Potassium, ppm | 0.7 | 2.1 |
| Zinc, ppm | 64.3 | 215.9 |
| Cadmium, ppm | 0.3 | 0.3 |
| Lead, ppm | 19.7 | 10.3 |
| Antimony, ppm | less than 2.6 | less than 2.6 |
| Chromium, ppm | less than 0.8 | 8.7 |
| Boron, ppm | less than 35.8 | less than 35.4 |
All tests were done on ashed samples using a Perkin-Elmer Atomic Absorption Spectrophotometer. The first nine or ten figures are the items considered worthy of attention. With the exception of a higher preferred calcium content in the paper case paper, these figures seem acceptable to the maker. Comments from conservators, however, are welcome.
Timothy Barrett![[Contents]](../../img/contbtn.gif)
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