Characterisation and restoration of a severely damaged paper archive from the Qing Dynasty.

Compared to the samples before degradation, the L*, a*, and b* parameters after dry-heat degradation showed statistically significant differences ( p ≤ 0.05), while after moist-heat degradation, they exhibited highly significant differences ( p ≤ 0.01). ΔE* of this model paper is above 5 before and after degradation under both conditions, belonging to the significant changes, according to National Bureau of Standards (NBS) units of colour difference 36 .

also in 132,142 other papers