Effects of plant dyes (walnut shell, tea plant, henna) on paper's stability in manuscript restoration

The stability of colored paper through dyes is very important in manuscript restoration. In this project Japanese papers (model papers) were colored with different dyes such as henna, walnut and tea. Artificial aging test was performed on these papers as well. Dye effect on stability of colored papers was measured through mechanical (folding endurance, tensile breaking and tear resistance) tests before/after aging test statistically; folding endurance test results in color level is significant. Tea colored paper sample was not as stable as model paper in folding resistance and the average of tea sample compare to model sample was 39.9 to 69.5. Folding endurance reduction was seen in tea and henna samples following aging test. The effects on tensile and tear resistance were not statistically different or dyes were not affected to cause any increase or decrease in stabilities. Scanning electron microscopy (SEM) images of model and dyed papers have demonstrated color and aging effects. The pH test upon henna sample, have shown acidic condition. Model paper was not the same as dyed papers in terms of weight and thickness. All samples include model and dyed papers, demonstrated decrease in brightness and yellowness and increase in redness following aging test.