Newly Developed Nano-Calcium Carbonate and Nano-Calcium Propanoate for the Deacidification of Library and Archival Materials

Table 3

Treatments of original documents (18th century) samples with nano-calcium propanoate in propan-2-ol.

pH before treatment	pH after treatment
Paper: 6.2 ± 0.1	Paper: 9.5 ± 0.1
Ink: 4.3 ± 0.1	Ink: 10.0 ± 0.1
Colour coordinates before treatment	Colour coordinates after treatment
Paper:	Paper:
L = 90.05 ± 0.76	L = 91.05 ± 1.15
a = −0.35 ± 0.02	a = −0.25 ± 0.06
b = +11.25 ± 0.45	b = +11.85 ± 1.09
Ink:	Ink:
L = 70.95 ± 0.07	L = 72.05 ± 0.03
a = +3.74 ± 0.68	a = +2.58 ± 0.32
b = +17.34 ± 0.89	b = +17.87 ± 0.96