Appendix 3: Comparison of Permanent Paper Standards

Final Report to Congress on the Joint Resolution to Establish a National Policy on Permanent Papers

----------------  -------------------  ---------------------------------------
    Property            NISO                         ISO
                                       ---------------------------------------
                   ANSI Z39.48-1992        ISO 9706          ISO/DIS 11108
                                          "permanent"          "archival
                                                               permanent"
----------------  -------------------  ------------------  -------------------

pH                7.5-10 (u)*          7.5-10              7.5-10
                  7.0-10 core (c)**
 
Alkaline reserve  2% minimum           20 g/kg CaCO3       20 g/kg CaCO3

Kappa number      7                    5                   5
(maximum)

Tear measure      5.25 mNm�/g (u)      70 g/m�:350 mN      70 g/m�:350 mN
                  3.50 mNm�/g (c)      25-70 g/m�:r=6w-70  25-70 g/m�:r=6w-70
                                       r = tear resistance r = tear resistance
                                       w = weight          w = weight

Other physical    none                 none                MIT folding
properties                                                 endurance 2.18

Other chemical    paper stock - no     none                paper stock - if
properties        more than 1% lignin                      other than cotton,
                                                           linen or ramie must
                                                           state content and
                                                           percent
------------------------------------------------------------------------------
 * (u) signifies an uncoated paper
** (c) a coated sheet

The pH and alkaline reserve requirements ensure that the paper is not acidic and will not become acidic over time. The kappa number requirement ensures that the paper is well-bleached, and therefore less likely to deteriorate due to oxidizable functional groups. And the tear index or tear resistance (as well as the folding endurance) is a measurement of strength which seems to predict fairly well an alkaline paper's durability under accelerated aging conditions.

Continue to Appendix 4: NARA Bulletin 95-7

Go back to Appendix 2: JCP "Option A" Paper Grades

Return to the Table of Contents

Home >> Resources >> Conservation Care >> Permanent Papers