Specifications for Archival Papers
We will break
these specifications into two parts. The first part will deal with those
requirements needed to insure the chemical purity of an archival paper or
paperboard. The second part will show how you can insure that high quality,
long chain cellulose has been used to make your archival paper by specifying
certain minimum physical strength parameters that must be met. These are, in
fact, the specifications we use for our Lig-free Type 1.
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.
As we have mentioned, certain textiles
such as silk and wool and certain photographic materials may be at risk in an
alkaline environment. We, therefore, have developed a special non-buffered
paper for use with these materials. The specifications are:
Specifications
for Photographic/Textile Conservation Paper
Part One
1. The
paper shall be made from fully bleached alpha cellulose pulp. It shall be free
of lignin, groundwood, particles of metal, waxes, plasticizers, alkaline
buffers, coloring agents, reducible sulfur, oxidizing chemicals, additives and
potentially harmful non-cellulose products. The surface of the paper should be
smooth and free from knots, shives and abrasive particles.
2. pH
range: The paper shall be in the neutral range.
3. Sizing:
Alkaline sizing shall be used in place of alum-rosin sizing.
4. Alkaline
reserve: The paper shall not contain calcium carbonate (CaCO3) or other
alkaline buffers.
5. Sulfur
content: The sulfur content shall be less than .0008% reducible sulfur as ASTMD
984-74 or TAPPI T 406, su 72.
6. Tarnishing
properties: The paper shall be non-tarnishing as per accelerated tarnishing
test ASTMD 2043-69 and TAPPI T 444, T 564. The paper must also pass the silver
tarnish test developed by T. J. Collings and F. J. Young, London, England.
Part Two
This paper meets the same high fold
(minimum 1000 double folds in the weakest direction at 1 kg.) and other
strength requirements as Lig-free , Type 1 in 5 through 10, part two.
Part
Three
Not
applicable since no coloring should be added to this paper.