Specifications for Lig-free Archival
Papers
Part One
1. The
paper should be made from fully bleached, alpha cellulose pulp. It should be
free of lignin, ground wood, waxes, plasticizers, reducible sulfur, oxidizing
chemicals and potentially harmful non-cellulose products. It should be free of
particles of metal with a maximum 30 ppm Fe and .7ppm Cu. The board shall be
hard sized with chemically saturated organic compounds to a Cobb size test of
not more than 100 grams per square meter (TAPPI) T-441 (os-69). The surface of
the paper should be smooth and free from knots, shives and abrasive particles.
2. pH
range: The paper should have a pH of not less than 8.5 nor more than 10.2.
3. Sizing:
Alkaline sizing should be used in place of alum-rosin sizing.
4. Alkaline
reserve: The paper should contain a minimum of 3% calcium carbonate (CaCO3), or
other suitable alkaline buffer.
Part Two
(These
strength specifications are for .010" thick paper.)
5. Abrasion
test: The paper shall show maximum fiber loss of one-tenth of one percent after
100 cycles according to TAPPI 476.
6. Smoothness
test: The paper should show a minimum smoothness of 195 Sheffield units following
TAPPI UM-518 test.
7. Folding
endurance test: The paper should withstand a minimum of 1,000 double folds in
the weakest direction at 1kg. load after conditioning according to TAPPI T 511.
8. Internal
tear resistance (Elmendorf): The paper shall have a minimum tear resistance of
350 gr. per sheet after conditioning TAPPI T414.
9. Stiffness
test: The paper should have 2800 stiffness units in the machine direction and
1400 stiffness units in the cross direction in accordance with TAPPI 489.
10. Bursting
strength: The paper should have a bursting strength of 300 pounds per square
inch when tested in accordance with TAPPI T 807.
Part
Three
(This
part pertains to those papers which are colored [dyed] such as our Lig-free ,
Type I.)
11. Color
UNLESS otherwise specified the outer surface of the paper should be natural tan
dyed with light-fast and non-bleeding dye.
12. Fading
test: When the paper is exposed in a standard fadeometer TAPPI UM-461 for 30
hours, the difference in brightness TAPPI T 452, measured on the exposed and
unexposed portions of the sample shall be less than 5 points.