Method for removing alpha-amylase in calligraphy and painting uncovering and application

Abstract

The invention belongs to the technical field of cultural relic protection, and particularly relates to a method for removing alpha-amylase in calligraphy and painting uncovering and application. The invention relates to a method for removing alpha-amylase during calligraphy and painting uncovering. A barium hydroxide solution is used for treating calligraphy and paintings uncovered by alpha-amylase; the barium hydroxide solution is prepared from barium hydroxide and a solvent; the solvent is water or methanol. In the process that alpha-amylase is adopted to uncover the calligraphy and painting, the barium hydroxide solution is further adopted to treat the calligraphy and painting, alpha-amylase residues are removed, excessive acidity can be neutralized, the alkalinity of the calligraphy and painting is enhanced, acidification of the calligraphy and painting is effectively prevented, the mechanical strength is improved, and long-term storage of the calligraphy and painting is facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of cultural relics protection, and particularly relates to a method for removing alpha-amylase in calligraphy and painting removal and application thereof. Background Art

[0002] In order to reproduce the artistic style of the original works, old calligraphy and paintings need to be remounted because the original mounting was not good and the shells have fallen off; or because of poor collection and storage, they have become damp and moldy, rotten and broken, and eaten by insects and rats; or because of being buried underground for a long time and rotting and overlapping.

[0003] The art of mounting antique calligraphy and paintings is a unique Chinese craft, primarily used for the restoration of ancient calligraphy and paintings. Mounting is the most crucial step in the process. This is because dust and moisture on the surface of calligraphy and paintings can easily compress them in environments with drastic temperature and humidity fluctuations, as well as under external forces. Furthermore, improper storage conditions can cause acidic gases such as sulfur dioxide and nitrogen dioxide in the air to combine with moisture to form acid rain. When these acid rain particles adhere to the surface of the painting and penetrate deep into it, they gradually acidify the components of the paper and pigments. In an acidic environment, the hydroxyl groups of cellulose in rice paper are easily attacked by hydrogen ions from the acid, breaking the cellulose molecular chains and weakening the paper. Therefore, an aqueous solution of α-amylase is used during the mounting and remounting process. α-amylase can quickly degrade the starch adhesive, allowing for a lossless separation of the painting from the mounting paper. However, any residual α-amylase on the paper makes it impossible to remount, necessitating removal. The existing technology uses chloramine T solution to remove α-amylase residues. However, since the chloramine in the chloramine T solution reacts with water to produce hypochlorous acid, the production of hypochlorous acid can easily cause the paper to become acidified during the aging process, thereby affecting the mechanical properties of the paper and being detrimental to the long-term preservation of calligraphy and painting. Summary of the Invention

[0004] In view of the technical problem in the prior art that when chloramine T solution is used to remove α-amylase residues, the production of hypochlorous acid easily causes acidification of paper during the aging process, affecting the mechanical properties of the paper and being detrimental to the long-term preservation of calligraphy and paintings, the present invention provides a method and application for removing α-amylase during the removal of calligraphy and paintings.

[0005] In the process of removing calligraphy and painting by using α-amylase, the present invention further uses barium hydroxide solution for treatment, which not only removes α-amylase residues but also neutralizes excessive acidity to enhance the alkalinity of the calligraphy and painting, effectively prevents the calligraphy and painting from acidifying during aging, improves mechanical strength, and is conducive to the long-term preservation of the calligraphy and painting.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for removing α-amylase from calligraphy and painting comprises treating calligraphy and painting removed with α-amylase using a barium hydroxide solution. The barium hydroxide solution removes the α-amylase from the calligraphy and painting while enhancing the alkalinity of the calligraphy and painting to prevent acidification.

[0008] It is further defined that the barium hydroxide solution is prepared by mixing barium hydroxide and a solvent; the solvent is water or methanol.

[0009] It is further defined that the concentration of the barium hydroxide solution is 20 g / L to 30 g / L.

[0010] It is further defined that the average peeling force of the calligraphy and painting after being peeled off with α-amylase using barium hydroxide solution is 0.8N~1.0N, and the average pH after aging is 7.9~8.182.

[0011] The invention discloses an application of a barium hydroxide solution in removing α-amylase residues during the removal of calligraphy and painting.

[0012] The invention discloses an application of a barium hydroxide solution in improving the pH value of calligraphy and painting during the removal process.

[0013] It is further defined that the barium hydroxide solution is prepared by mixing barium hydroxide and a solvent; the solvent is water or methanol.

[0014] It is further defined that the concentration of the barium hydroxide solution is 20 g / L to 30 g / L.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. In the process of removing the core of calligraphy and painting by using α-amylase, the present invention further uses barium hydroxide solution to treat the core of the painting, which not only removes the residual α-amylase, but also neutralizes excessive acidity to enhance the alkalinity of the calligraphy and painting, effectively preventing the calligraphy and painting from acidifying during the aging process, improving the mechanical strength, and facilitating the long-term preservation of the calligraphy and painting.

[0017] 2. The present invention has found through testing that the samples with residual α-amylase treated with barium hydroxide solution have an average peeling force of 0.8N~1.0N, which can inactivate the activity of α-amylase, thereby achieving the removal of α-amylase; at the same time, the average pH after aging is 7.9~8.182, indicating that after treatment with barium hydroxide solution, the pH value of calligraphy and painting can also be improved, preventing the calligraphy and painting from acidifying during aging, which is beneficial to preservation.

[0018] 3. Through research, the present invention preferably uses a methanol solution of barium hydroxide to treat the center of a calligraphy or painting that has been coated with α-amylase. On the one hand, since metallic barium, as a heavy metal, can effectively kill the residual α-amylase and reduce its activity, it is ensured that the α-amylase remaining in the center of the calligraphy or painting is removed. On the other hand, the methanol solution of barium hydroxide is weakly alkaline, which can neutralize the excessive acidity of the paper in the center of the calligraphy or painting, and significantly enhance the alkalinity of the paper in the center of the calligraphy or painting, so that the paper has the ability to resist the erosion of acidic substances generated by itself or acidic gases in the air, and is not easily acidified after aging.

[0019] 4. The method for removing the core of calligraphy and painting provided by the present invention adopts inorganic metal salts and organic solvents (methanol) to not only remove α-amylase residues, but also prevent the calligraphy and painting from aging and acidification. It is not only simple to operate and easy to implement, but also prolongs the storage period of calligraphy and painting. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 To compare the effects of removing simulated samples using α-amylase aqueous solution;

[0021] Figure 2 The comparison effect is obtained by removing a simulated sample without using α-amylase aqueous solution;

[0022] Figure 3 is the morphology of untreated paper;

[0023] Figure 4 Topographical diagram of water peeling paper;

[0024] Figure 5 Topographic image of paper peeled off for α-amylase aqueous solution;

[0025] Figure 6 This is the morphology of paper treated with a methanol solution of barium hydroxide;

[0026] Figure 7 Average peel force after remounting of papers with different treatments;

[0027] Figure 8 This is a real picture of the sample treated with α-amylase after being remounted;

[0028] Figure 9 This is a comparison chart of the average peeling force of paper treated with methanol solutions of different concentrations of barium hydroxide;

[0029] Figure 10 Comparison of pH values of paper after treatment with methanol solutions of different concentrations of barium hydroxide; DETAILED DESCRIPTION

[0030] The technical solution of the present invention will now be further described with reference to the accompanying drawings and embodiments, but the present invention is not limited to the following implementations.

[0031] Unless otherwise defined, technical or scientific terms used in the present invention shall have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0032] Technologies, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such technologies, methods, and equipment should be considered part of the specification.

[0033] It should also be understood that the specific embodiments described above are only used to explain the present invention, and the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, which should be covered by the scope of protection of the present invention / invention.

[0034] The first technical solution provided by the present invention is a method for removing α-amylase during the removal of calligraphy and painting.

[0035] A method for removing α-amylase from calligraphy and painting comprises treating calligraphy and painting removed with α-amylase using a barium hydroxide solution. The barium hydroxide solution removes the α-amylase from the calligraphy and painting while enhancing the alkalinity of the calligraphy and painting to prevent acidification.

[0036] In the present invention, the barium hydroxide solution is prepared from barium hydroxide and a solvent; the solvent is water or methanol. Preferably, the solvent is methanol.

[0037] In the present invention, the concentration of the barium hydroxide solution is 20 g / L to 30 g / L. The concentrations of the barium hydroxide solution are 20 g / L, 22 g / L, 25 g / L, 27 g / L, and 30 g / L; preferably, the concentration of the barium hydroxide solution is 20 g / L.

[0038] In the present invention, the calligraphy and painting removed by α-amylase are treated with a barium hydroxide solution, and the average peeling force is 0.8N-1.0N and the average pH is 8.5-10.45.

[0039] The second technical solution provided by the present invention is: the barium hydroxide solution is used in the removal of calligraphy and painting.

[0040] Application of barium hydroxide solution in removing α-amylase residues during painting and calligraphy removal.

[0041] The application of barium hydroxide solution in increasing the pH value of calligraphy and painting during the removal process.

[0042] When used, the barium hydroxide solution is prepared by mixing barium hydroxide with a solvent; the solvent is water or methanol. Preferably, the solvent is methanol.

[0043] When used, the concentration of the barium hydroxide solution is 20 g / L to 30 g / L. Preferably, the concentration of the barium hydroxide solution is 20 g / L.

[0044] The technical solution protected by the present invention is described below with reference to specific experimental studies.

[0045] It should be noted that, unless otherwise specified, the chemicals and reagents used in the following examples are all commercially available products.

[0046] It should be noted that, unless otherwise specified, the operations in the following embodiments are all conventional operations in the art.

[0047] 1. Preparation of simulation samples

[0048] Two pieces of rice paper are pasted together to ensure that only half of the paper is in a bonded state. The other half that is not bonded with glue is clamped with a universal material testing machine fixture for later testing of peel strength. After that, it is aged for 6 days at a temperature and relative humidity of 80°C and 65% respectively. Finally, the sample is cut into strips with a width of 30mm. Then, a simulated sample consisting of two parts, bonded and unbonded, can be obtained.

[0049] 2. Experimental testing

[0050] 2.1. Using α-amylase aqueous solution to remove old calligraphy and paintings

[0051] It is proposed to use a 0.05% mass fraction of α-amylase aqueous solution for stripping, and compare the stripping effect of the water-treated sample. The comparison effect is as follows Figure 1 and Figure 2 shown.

[0052] Figure 1 Middle: (a) The sample after mounting; (b) The effect after half of the frame is removed; (c) The effect after the frame is completely removed; Figure 2 In the figure, (a) and (b) are the process diagrams of the water-steaming method; (c) is the process of the hand-rubbing method.

[0053] Figure 1 and Figure 2 Results showed that after ten minutes of treatment with a 0.05% α-amylase aqueous solution, the sample could be removed very smoothly, with a smooth surface and no noticeable fiber breakage. However, using the water-suffocating method resulted in damage to the paper, resulting in a rough surface and noticeable fiber breakage. This demonstrates that α-amylase does not damage paper when treating starch adhesives.

[0054] 2.2 Surface morphology and roughness analysis

[0055] The surface morphology of untreated paper, water-peeled paper, paper peeled with an α-amylase aqueous solution, and paper treated with a methanolic barium hydroxide solution were observed using a Keyence VK-X260K shape analysis laser microscope, and their roughness parameters were obtained. Calibration and analysis were performed using Keyence Multi-File Analysis software. The analysis and test results are shown in Table 1. Figure 3 、 Figure 4 、 Figure 5 and Figure 6 shown.

[0056] Figure 3 In the figure, (a) is the 2D topography of the untreated paper; (b) is the 3D topography and roughness parameters of the untreated paper; Figure 4 In the figure, (a) is the 2D topography of the water-release paper; (b) is the 3D topography and roughness parameters of the water-release paper; Figure 5 In the figure, (a) is a 2D topography of the paper peeled off by the α-amylase aqueous solution; (b) is a 3D topography and roughness of the paper peeled off by the α-amylase aqueous solution; Figure 6 In the figure, (a) is the 2D morphology of the paper treated with methanol solution of barium hydroxide; (b) is the 3D morphology and roughness of the paper treated with methanol solution of barium hydroxide.

[0057] Table 1 Roughness parameters

[0058]

[0059] Table 1, Figure 3 、 Figure 4 、 Figure 5 and Figure 6 The analysis results are as follows:

[0060] (1) Untreated paper surface S a 5.119μm, S z 74.501μm; S of water-peelable paper a 4.142μm, S z The S of the paper removed by α-amylase is 114.665μm. a 4.599μm, S z The S of the paper treated with barium hydroxide methanol solution is 80.03 μm. a 5.63μm, S z 98.59μm. S a and S z It is mainly used to characterize the geometric height of the peaks formed on the surface of the test sample. The larger the measured value, the rougher the surface. Therefore, it can be seen that the paper peeled off by ultrapure water has a rough surface with ups and downs instead of the originally smooth surface.

[0061] (2) Untreated paper surface Str The S of water-releasable paper is 0.403. tr The S of the paper stripped by α-amylase is 0.573. tr The S of the paper treated with barium hydroxide methanol solution is 0.371. tr The value is 0.638. The closer this value is to 0, the more uniform the streaks formed on the surface. Conversely, the closer it is to 1, the more uneven the streaks are. Testing found that the streaks formed on the surface of water-peeled paper were less uniform, while the streaks formed on the surface of paper peeled with α-amylase were more uniform.

[0062] (3) Untreated paper surface S pc 3324.591mm -1 , water-releasable paper S pc 5447.672mm -1 , α-amylase stripped paper S pc 4059.631mm -1 , S of paper treated with methanol solution of barium hydroxide pc 3591.33mm -1 . S pc It is used to characterize the sharpness of the protrusions formed on the rough interface. The larger the value, the sharper the surface. This shows that the water-released paper surface forms a sharp protrusion.

[0063] (4) Untreated paper surface S dr The S of water-releasable paper is 3.36. dr The S of the paper stripped by α-amylase is 3.56. dr The S of paper treated with barium hydroxide methanol solution is 2.499. dr 2.98. dr It is used to characterize the increase ratio of the surface area formed by the rough surface to the original surface area, S dr The larger the value is, the larger the area occupied by the rough interface is, which means that the surface area of the water-released paper increases.

[0064] The above analysis shows that the surface roughness of water-peeled paper increases, forming a large number of sharp and unevenly distributed concave-convex interfaces, which increases the surface area; while the surface roughness of paper treated with methanol solution of barium hydroxide does not change much.

[0065] 2.3. Inactivation of residual α-amylase after removal

[0066] To restore the original appearance of calligraphy and paintings, they need to be remounted after removal. However, residual α-amylase may still remain on the surface of the painting after treatment, breaking down the applied paste during subsequent processing. This can lead to obvious problems such as hollowing and warping in the painting after subsequent treatment. This study used a methanolic solution of barium hydroxide to inactivate the residual α-amylase. To demonstrate the effectiveness of the inactivation, a higher concentration of α-amylase solution (0.2% by mass) was used for the study.

[0067] Determine the average peeling force of untreated paper and paper treated with methanolic barium hydroxide solution after remounting. Figure 7 As shown; the effect of the sample treated with α-amylase after re-mounting is shown in Figure 8 As shown, among which: (a) is a remounted sample with α-amylase residues; (b) is a remounted sample treated with α-amylase and naturally falling off and separating.

[0068] Depend on Figure 7 and Figure 8 The results show that the average peel force of remounted paper treated with a methanolic barium hydroxide solution and containing residual α-amylase was similar to that of untreated paper. This difference may be due to the difficulty in precisely controlling the concentration of the starch adhesive during the second mounting process. However, the α-amylase-treated sample exhibited hollowing and spontaneous peeling after remounting. This suggests that a methanolic barium hydroxide solution can effectively inactivate α-amylase and does not affect the secondary mounting of calligraphy and paintings.

[0069] 2.4 Effects of different concentrations of barium hydroxide in methanol on α-amylase activity

[0070] The paper samples treated with α-amylase were treated with 10g / L, 15g / L, 20g / L, 25g / L, and 30g / L of methanol solution of barium hydroxide, and compared with the samples treated with α-amylase and blank paper samples. After the paper samples were dried, the peeling strength of the samples was tested. The results are as follows: Figure 9 shown.

[0071] from Figure 9As can be seen, as the barium hydroxide concentration increases, the average peeling strength of the paper first decreases and then increases. Barium hydroxide methanol solutions at concentrations of 10g / L and 15g / L reduce α-amylase activity, but some α-amylase will still remain, resulting in a decrease in the paper's peeling strength. However, the peeling strength of 20g / L, 25g / L, and 30g / L barium hydroxide methanol solutions is almost identical to that of untreated blank paper. This indicates that barium hydroxide methanol solutions in the 20g / L to 30g / L concentration range can inactivate α-amylase. Based on treatment cost considerations, a 20g / L barium hydroxide methanol solution is preferred for treating paper.

[0072] 2.5 Effect of different concentrations of barium hydroxide methanol solution on the pH of paper

[0073] Treat paper samples with 10g / L, 15g / L, 20g / L, 25g / L, and 30g / L barium hydroxide methanol solutions, and test the pH values of the paper samples after they are dried. The test results are as follows: Figure 10 shown.

[0074] from Figure 10 It can be seen that the pH of the paper samples treated with 10g / L, 15g / L, 20g / L, 25g / L, and 30g / L barium hydroxide methanol solutions ranged from 9.5 to 10, indicating that the use of barium hydroxide methanol solution can increase the pH of paper, enhance its alkalinity, prevent acidification of calligraphy and painting, and is beneficial to the preservation of calligraphy and painting. Figure 8 When the concentration range is 20g / L to 30g / L, the methanol solution of barium hydroxide will cause the activity of α-amylase to be lost. Therefore, 20g / L methanol solution of barium hydroxide is selected to treat paper.

[0075] 2.6. Determination of pH and alkali reserve of paper after deacidification

[0076] Alkali reserve refers to the amount of alkaline buffering substances added to a sample. These alkaline substances are primarily used to neutralize acidic substances generated by the calligraphy and painting itself and the surrounding environment, slowing the acidification and aging of the collection and extending its shelf life. A higher alkaline reserve indicates a good buffering capacity, capable of neutralizing more acidic substances. However, as the surrounding acidic substances are generated, the alkaline substances in the paper are also consumed. This is a continuous process. Therefore, the pH value and alkaline reserve of paper are tested and studied.

[0077] In this study, the simulated sample (i.e., paper) was first treated with a 0.2% mass fraction α-amylase solution. The paper was then further treated with a 20 g / L methanol solution of barium hydroxide and a 20 g / L aqueous solution of barium hydroxide. The pH and alkaline reserve of the paper after deacidification were measured. The results are shown in Table 2.

[0078] Among them: Untreated is the prepared simulated sample, that is, it has not undergone any treatment; Chloramine T solution treatment is a simulated sample (i.e., paper) prepared by first treating it with a 0.2% mass fraction α-amylase solution; and then further treating it with a 20 g / L chloramine T solution, where 1, 2, 3, 4, and 5 represent the number of tests.

[0079] Table 2 pH and alkali reserve determination of paper after deacidification

[0080]

[0081] Table 2 shows that treatment with barium hydroxide significantly enhances the alkalinity of the paper. Due to the addition of alkaline fillers during the production of handmade Xuan paper, Xuan paper itself is slightly alkaline. However, the use of alum in mounting calligraphy and paintings, as well as aging during storage, gradually acidifies the paper, lowering its pH. Treatment with barium hydroxide, however, re-enhances the alkalinity of the paper. Specifically, untreated paper exhibits a strong acidity, with an average pH of 4.078. After treatment with α-amylase solution and chloramine T solution, the average pH reached 8.522. After treatment with α-amylase solution and aqueous barium hydroxide solution, the average pH reached 8.714, with an alkali reserve of 0.701 mol / kg. After treatment with α-amylase solution and methanolic barium hydroxide solution, the average pH reached 9.936, with an average alkali reserve of 1.259 mol / kg. It was found that treatment with barium hydroxide solution increased the paper's alkali reserve, raising its pH from 4.078 to 8.714, reaching a maximum of 9.936. Furthermore, after aging the paper for six days, the average pH of the paper after treatment with α-amylase solution and chloramine T solution was 6.094; after treatment with α-amylase solution and barium hydroxide aqueous solution, the average pH was 7.900; and after treatment with α-amylase solution and barium hydroxide methanol solution, the average pH was 8.182. Compared to treatment with chloramine T solution, treatment with α-amylase solution in methanol and barium hydroxide aqueous solution was less susceptible to acidification after aging. Therefore, treatment with barium hydroxide in methanol and barium hydroxide aqueous solution not only inactivates the α-amylase solution but also protects against acidification caused by environmental changes, extending the shelf life of the calligraphy and painting. Furthermore, treatment with barium hydroxide in methanol resulted in a higher alkali reserve and better resistance to acidification, maximizing the shelf life of the calligraphy and painting. Preferably, during the removal of calligraphy and painting, a methanol solution of barium hydroxide may be used to treat the calligraphy and painting with residual α-amylase.

[0082] 2.7 Physical performance impact test

[0083] Three groups of papers, each treated with 0.05% α-amylase, were used for three experiments. The control group received no treatment; experimental group 1 was treated with a methanol solution of barium hydroxide, and experimental group 2 was treated with an aqueous solution of barium hydroxide. The three treated paper samples were then tested for tensile strength, folding resistance, tear resistance, softness, whiteness, and pH. The results are shown in Table 3.

[0084] Table 3 Impact on the physical properties of paper

[0085]

[0086]

[0087] The test data in Table 3 show that the differences in softness, whiteness, and folding resistance before and after aging between Experimental Group 1 and the control group were small and within the acceptable error range. This indicates that the concentration of barium hydroxide in methanol had no short-term impact on these physical properties of paper. However, paper treated with the barium hydroxide solution showed a decrease in softness and whiteness before aging, but after wet-heat aging, its overall performance was superior to that of the control. Furthermore, the barium hydroxide in methanol solution significantly increased the acidity of the paper. Combined with the above results, the barium hydroxide in methanol solution significantly increased the acidity of the paper, indicating that treatment with the barium hydroxide in methanol solution is more effective in removing acid.

[0088] After six days of wet heat aging, the study found that the paper's transverse and longitudinal tear resistance, softness, tensile strength, folding resistance, whiteness, and acidity all decreased compared to their original values. This is because during the wet heat aging process, the cellulose, hemicellulose, and lignin molecules in the paper are susceptible to oxidation, producing carbonyl or hydroxyl groups, which promote their hydrolysis and degradation, resulting in a loss of fiber strength. The organic acids produced by oxidation also reduce the pH. The formation of chromophores causes the paper's color to change, darkening, and inevitably decreasing its whiteness. Furthermore, the presence of water molecules disrupts hydrogen bonds in the pulp, reducing interfiber adhesion and strength. During this process, the pH decreases as the oxidation process progresses, due to the production of organic acids. However, a comparison of the various properties after wet heat aging revealed minimal differences between the control and experimental groups, indicating that the methanolic barium hydroxide solution has no effect on the durability of the paper.

[0089] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for removing α-amylase from calligraphy and painting, characterized in that: The barium hydroxide solution is used to treat the calligraphy and paintings that have been removed with α-amylase. While removing the α-amylase on the calligraphy and paintings, the barium hydroxide solution enhances the alkalinity of the calligraphy and paintings to prevent acidification.

2. The method for removing α-amylase from calligraphy and painting according to claim 1, wherein: The barium hydroxide solution is prepared from barium hydroxide and a solvent; the solvent is water or methanol.

3. The method for removing α-amylase from calligraphy and painting according to claim 1, characterized in that: The concentration of the barium hydroxide solution is 20 g / L to 30 g / L.

4. The method for removing α-amylase from calligraphy and painting according to claim 1, characterized in that: The average peeling force of the calligraphy and paintings removed by α-amylase after treatment with barium hydroxide solution was 0.8N-1.0N, and the average pH after aging was 7.9-8.

182.

5. Application of a barium hydroxide solution in removing α-amylase residues during painting and calligraphy removal.

6. Application of a barium hydroxide solution in increasing the pH value of calligraphy and painting during the removal process.

7. The use according to claim 5 or 6, characterized in that The barium hydroxide solution is prepared from barium hydroxide and a solvent; the solvent is water or methanol.

8. The use according to claim 5 or 6, characterized in that The concentration of the barium hydroxide solution is 20 g / L to 30 g / L.

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