On the Mechanisms of Marble Deterioration of Antonio Canova Cenotaph in Santa Maria Gloriosa dei Frari Basilica in Venice

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper features a scientific database of the deterioration processes affecting the funerary cenotaph, the monument dedicated to Antonio Canova, located in the Basilica of the Frari in Venice. The study, based on thermographic examinations, moisture content analysis, and examinations of deteriorating and exfoliating surfaces at both macroscopic and microscopic levels, as well as the detection of salt contents from the different structural units of the monument, infer the moisture transfer from the basement brick structures to the upper marble structures through capillary rise as the possible reason for the observed decay. The study presents several interesting results showcasing the type and extent of decay of the structures and suggests the conservation strategies that are worth publication. However, the paper has several flaws in its present form. Much of my comments are annotated directly in the manuscript PDF. Significant comments are given below.

1. Section 4 ‘Materials and Methods’:

The section lacks essential information regarding the sampling process. Details such as the procedure for sample collection, the specific locations on the monument from which samples were taken, and photographs or visual documentation of the collected samples should be included. While XRD and XRF analyses are mentioned, the corresponding results are not presented or discussed in the paper. The author is also advised to provide information about the instrumentation used for each analysis, including relevant parameters and the sample preparation methods employed.

2. Section 5 ‘Results’:

This section requires significant revision and reorganization. The results should be presented in a clear and structured manner, focusing on the actual observations and data generated from the study. However, the current version prematurely moves into interpretation and conclusions without adequately establishing the supporting scientific evidence. This approach undermines the clarity and credibility of the findings. Additionally, the captions of figures showing analytical results (e.g., Figures 8, 9, and 22) are insufficiently detailed. The captions should clearly describe the analytical techniques used and provide context to help readers understand the significance of the results.

3. I recommend that the author restructure the manuscript by presenting all experimental data, analytical results, and direct observations clearly in Section 5: Results. A separate section, Section 6: Discussion, should then be introduced to provide a focused and detailed interpretation of the findings. This standard separation between results and discussion will enhance the clarity, coherence, and scientific rigor of the manuscript.
4. The photographs illustrating the various decay, deterioration, and exfoliation features could be more effectively presented as a grouped figure or image panel in the early part of the manuscript. This would provide readers with a visual context and help streamline references to these features throughout the Results and Discussion
5. The conclusion attributing the observed decay to moisture transfer from the basement brick structures to the upper marble elements via capillary rise requires further evidence and clarification. As per the description and the data presented in Figure 9, the lower structural segments display lower chloride content than the upper portions. Given the differing porosity between the lower brick units and the upper marble components, a gradual decrease in salt accumulation with height would typically be expected if capillary action were dominant. However, this trend is not evident. Instead, salt precipitation and deterioration appear to be localized and irregular, such as the concentration observed on the chest of the Sleeping Genius. Additional data and more robust justification are needed to support capillary rise as the primary mechanism for salt accumulation and decay.
6. I recommend that the author also consider other potential environmental factors—such as thermal stress due to temperature fluctuations, air pollution, increased moisture exposure, and biological growth—before drawing definitive conclusions. A broader consideration of these variables would strengthen the interpretation and ensure a more comprehensive understanding of the observed deterioration processes.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

The manuscript contains several spelling errors and vague or unclear sentences that detract from the overall readability. A thorough language edit is strongly recommended to improve clarity, coherence, and academic quality.

Author Response

Response to Reviewer 1 Comments

The paper features a scientific database of the deterioration processes affecting the funerary cenotaph, the monument dedicated to Antonio Canova, located in the Basilica of the Frari in Venice. The study, based on thermographic examinations, moisture content analysis, and examinations of deteriorating and exfoliating surfaces at both macroscopic and microscopic levels, as well as the detection of salt contents from the different structural units of the monument, infer the moisture transfer from the basement brick structures to the upper marble structures through capillary rise as the possible reason for the observed decay. The study presents several interesting results showcasing the type and extent of decay of the structures and suggests the conservation strategies that are worth publication. However, the paper has several flaws in its present form. Much of my comments are annotated directly in the manuscript PDF. Significant comments are given below.

Thank you for your comments I tried to follow as much as possible according other reviewers’ comments

 1. Section 4 ‘Materials and Methods’:

The section lacks essential information regarding the sampling process. Details such as the procedure for sample collection, the specific locations on the monument from which samples were taken, and photographs or visual documentation of the collected samples should be included. While XRD and XRF analyses are mentioned, the corresponding results are not presented or discussed in the paper. The author is also advised to provide information about the instrumentation used for each analysis, including relevant parameters and the sample preparation methods employed.

Section 4 was improved. Sampling was carried out according to EN 16085. Location of sampling area were detailed. Instrumentation and preparation of sample were also included.

See revised version.

2. Section 5 ‘Results’:

This section requires significant revision and reorganization. The results should be presented in a clear and structured manner, focusing on the actual observations and data generated from the study. However, the current version prematurely moves into interpretation and conclusions without adequately establishing the supporting scientific evidence. This approach undermines the clarity and credibility of the findings. Additionally, the captions of figures showing analytical results (e.g., Figures 8, 9, and 22) are insufficiently detailed. The captions should clearly describe the analytical techniques used and provide context to help readers understand the significance of the results.

Section was reorganized according to the suggestion and results were presented more clearly.

Premature interpretations were moved in the Discussion section.

Photograph captions were also detailed

See revised version

3. I recommend that the author restructure the manuscript by presenting all experimental data, analytical results, and direct observations clearly in Section 5: Results. A separate section, Section 6: Discussion, should then be introduced to provide a focused and detailed interpretation of the findings. This standard separation between results and discussion will enhance the clarity, coherence, and scientific rigor of the manuscript.

 

Section was restructured according to your suggestion.

 

4. The photographs illustrating the various decay, deterioration, and exfoliation features could be more effectively presented as a grouped figure or image panel in the early part of the manuscript. This would provide readers with a visual context and help streamline references to these features throughout the Results and Discussion

 

Photographs were grouped and detailed described.

 

5. The conclusion attributing the observed decay to moisture transfer from the basement brick structures to the upper marble elements via capillary rise requires further evidence and clarification. As per the description and the data presented in Figure 9, the lower structural segments display lower chloride content than the upper portions. Given the differing porosity between the lower brick units and the upper marble components, a gradual decrease in salt accumulation with height would typically be expected if capillary action were dominant. However, this trend is not evident. Instead, salt precipitation and deterioration appear to be localized and irregular, such as the concentration observed on the chest of the Sleeping Genius. Additional data and more robust justification are needed to support capillary rise as the primary mechanism for salt accumulation and decay.

 

Data presented in figures 8 and 9 were improved and a table with the data was also introduced.

Regarding the interpretation of the results presented (the increase of chlorides content with height is in agreement with Arnod findings and our findings in Santa Maria dei Miracoli church) answer to the comments in the pdf attached to paper.

 

6. I recommend that the author also consider other potential environmental factors—such as thermal stress due to temperature fluctuations, air pollution, increased moisture exposure, and biological growth—before drawing definitive conclusions. A broader consideration of these variables would strengthen the interpretation and ensure a more comprehensive understanding of the observed deterioration processes.

I take into consideration also the influence of pollution, but in very few cases sulphates due to sulphation process were found. In conclusion, according to our measurements, capillary rise process is the main mechanism.

Please see attachement

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The introduction  could be improved. In my opinion papers on different restoration processes of other areas of Frari Basilica should be cited such as Casarin 2004, Lionello et al  2015 Gottardi et al 2015   and others.

Scales are missing in some figures, being especially necessary in figure 6 and 15.

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Dear Sirs, the comments are in the attached file. Best regards.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

The author is congratulated on the research carried out and the findings presented. The following actions are recommended in detail:
1. Review formal aspects related to:
a. Paragraph alignment
b. Review the spacing between figure captions and figures
c. Include specific identification, either a or b, in each figure itself.
d. There are excessively short paragraphs, of 2 or 3 lines, which should be linked to preceding or subsequent content.
e.    Improve the quality (resolution) of figure 7
f.    Figures 10 to 13 should be placed together, properly identified and highlighting the relevant aspect, area, or element of each one. The same applies to figures 20 and 21.
g.    The size of several figures is excessive and should be reviewed in terms of their usefulness for understanding the work.
h.    Delete lines 455 and 456.
i.    Complete the authorship of several bibliographic references.
j.    Complete the year, editorial data, or other components of several bibliographic references.

2.    Verify, clarify, or argue the following content:
a.    Include some reference to location and time period in the abstract.
b.    Include relevant quantitative data in the abstract.
c. In the introduction, it would be advisable to expand on content such as the contextualization of the problem of this type of monument in the world, as well as applicable conservation actions, whether successful or not. Other notable omissions include the architectural contextualization of the site where it is located, the environmental conditions to which the property is exposed, and the details of access to the monument.
d.    There is content in the introduction that should be moved to Previous Studies due to its cause-and-effect relationship.
e.    There is no section describing the petrographic characterization of the materials that make up the work. What type of marble is it?
f.    The section on previous studies should provide a minimum timeline of all those carried out and their scope, as well as their implications for conservation. It is not clear how many there are, when they were carried out, or other details.
g.    The contents of section 3 should be presented in a more concise and clear manner in the introduction and in section 2.
h.    Section 4 needs:
i.    A figure or planimetry of the location of the samples taken, duly identified.
ii.    It would be important to know how many samples have been collected and how they have been analyzed based on the techniques applied. 
iii.    Justify the number of samples.
iv.    The information on techniques, processes, and research instruments used in the different tests carried out must be completed.
i. Section 5.1 is not entirely a result, it is a characterization of the monument. Much of its content should be relocated. In addition, the processes followed should be stated in the methodology if they are part of the research process followed by the author. Furthermore, comparing brick with marble is not appropriate, especially without being technically characterized. This type of content should be reviewed and corrected.
j. Section 5.2 confirms that the brick elements, due to their impact on the marble monument, should also have been characterized in order to understand their nature. The findings presented need to be referenced with sources.
k. Section 5.3 presents content specific to the methodology that must necessarily be relocated. The findings presented need to be referenced with sources.
l.    The Discussion section is confusing. It does not clearly relate to the findings and shows no connection to topics such as the previous studies to which the work refers. The conservation actions lose relevance considering the above. 
m.    The Conclusions section contains content associated with the Discussion and conservation strategies. Therefore, it needs to be rewritten.

Author Response

Please see attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The revised paper shows significant improvement over the previous version. However, I still find several flaws which, although minor, require revision to bring the manuscript to a publishable standard. A few of my critical comments have been annotated in the PDF of the manuscript, which I have attached to the portal. Additional specific comments are provided below.

1. In response to my earlier comment requesting information on the Venetian churches and historic buildings mentioned in the text (Page 3, Line 7 in the previous version of the manuscript), the authors have provided a list of published studies and noted that, according to the rules of Heritage journal, self-citations cannot exceed a certain percentage. The authors expressed concern about citing their own papers co-authored with others. While inappropriate self-citations should indeed be avoided, relevant self-authored works can and should be cited when they are essential for discussion, context, and justification of the content. Therefore, I suggest that the authors present a summary of relevant case studies that can be related to the present work.
2. There are a few figures (Figures 7, 8, 9, 12, and 14) and their captions appear cluttered and unorganized, and the captions do not clearly describe the individual photographs. I recommend reorganizing the photographs into neatly arranged panels within a single figure, labeled sequentially as (a)–(e) within the images, and providing corresponding explanations for each panel in the figure caption. It is sufficient to write, for example, “Figure 7” at the beginning of the caption and then list the panels as (a), (b), (c), etc., without repeating “Figure 7a” or “Figure 7b.” The paper labels shown in the photographs may not be easily readable. I suggest identifying the images by adding letter labels directly onto them. This approach will improve clarity and the overall visual presentation.
3. Following the extensive data and results sections, the discussion appears rather scanty. The authors should draw upon the presented results and data in this section to provide a more detailed interpretation and propose their own insights, supported by the findings and any other published data. This critical engagement with the results is missing in the current version. In addition, forming paragraphs with only one or two sentences is not good writing practice. Related ideas should be combined into well-developed paragraphs to improve readability and coherence.
4. Please refer to my comments in the PDF of the manuscript for several other corrections in the text and figures. I also recommend a thorough language check to improve clarity and readability.

 

Comments for author File: Comments.pdf

Author Response

Thank you for the comments of the first revision. I improved the paper according to your comments

The revised paper shows significant improvement over the previous version. However, I still find several flaws which, although minor, require revision to bring the manuscript to a publishable standard. A few of my critical comments have been annotated in the PDF of the manuscript, which I have attached to the portal. Additional specific comments are provided below.

1. In response to my earlier comment requesting information on the Venetian churches and historic buildings mentioned in the text (Page 3, Line 7 in the previous version of the manuscript), the authors have provided a list of published studies and noted that, according to the rules of Heritage journal, self-citations cannot exceed a certain percentage. The authors expressed concern about citing their own papers co-authored with others. While inappropriate self-citations should indeed be avoided, relevant self-authored works can and should be cited when they are essential for discussion, context, and justification of the content. Therefore, I suggest that the authors present a summary of relevant case studies that can be related to the present work.

 

I included some papers published on the subject including some self-citations.

 

2.There are a few figures (Figures 7, 8, 9, 12, and 14) and their captions appear cluttered and unorganized, and the captions do not clearly describe the individual photographs. I recommend reorganizing the photographs into neatly arranged panels within a single figure, labeled sequentially as (a)–(e) within the images, and providing corresponding explanations for each panel in the figure caption. It is sufficient to write, for example, “Figure 7” at the beginning of the caption and then list the panels as (a), (b), (c), etc., without repeating “Figure 7a” or “Figure 7b.” The paper labels shown in the photographs may not be easily readable. I suggest identifying the images by adding letter labels directly onto them. This approach will improve clarity and the overall visual presentation.

 

Thank you. Figures were reorganized according to your suggestion.

 

3. Following the extensive data and results sections, the discussion appears rather scanty. The authors should draw upon the presented results and data in this section to provide a more detailed interpretation and propose their own insights, supported by the findings and any other published data. This critical engagement with the results is missing in the current version. In addition, forming paragraphs with only one or two sentences is not good writing practice. Related ideas should be combined into well-developed paragraphs to improve readability and coherence.

 

I made improvement in the discussion section and according to me, thanks to the reviewer comment, the interpretation data is ameliorated.

Regarding the short paragraphs according to me it is clearer to explain the deterioration mechanisms.

4. Please refer to my comments in the PDF of the manuscript for several other corrections in the text and figures. I also recommend a thorough language check to improve clarity and readability.

 

Done

Please see attachment

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

The authors are to be congratulated for the adjustments made to the paper. However, although this makes the research more relevant, unfortunately the paper is presented in a disorderly manner, and it is suggested that the authors take more care with the structure and placement of elements. In detail, I comment:

1. The title on line 40 cannot be left alone on the page.
2. The paragraph beginning on line 41 needs to be cited.
3. In section 2, it is necessary to know when the previous studies were conducted. The techniques and results are discussed, but not the periods or moments in which they were applied. It would be important to include the year in order to differentiate between the different processes carried out. This is included in the Conclusions, so it is understood that the information exists.
4. Figures 3 and 4 should be combined. The fragmentation of the text is unnecessary, and with proper identification, they can be perfectly referenced in the text. The same applies to Figures 10 and 11.
5. The citation of sources in Figure 4 contains errors. Review the standards required by the journal.
6. The paragraphs beginning on lines 119 and 121 should be merged.
7. The identification with a) and b) in Figure 5, Figure 7, Figure 8, Figure 9, Figure 12, Figure 14, Figure 16, Figure 17, Figure 18, Figure 19, and Figure 21 should be indicated in the figure itself. Use a graphics software such as Photoshop to include these letters directly in the figure. The organization of Figure 7 could be improved.
8. The paragraph beginning on line 148 should be merged with the following paragraphs.
9. The format of the cross-reference text should be unified; several writing styles are used and do not conform to the applicable standard in the journal.
10. The paragraphs beginning on lines 255 and 258 should be merged.
11. The discussion section needs to be expanded. For example, are the techniques used sufficient for diagnosis? Is there anything else that could further clarify the situation? Are there other cases of monuments that contribute to understanding the phenomena identified and their treatment? Is it possible to envisage greater losses than the current ones in the short or medium term?
In addition, it would be important to explain, with sources, how an element that is close to but not part of the monument affects its conservation. This is the case with the architectural elements of the site where the cenotaph is located.
12. Regarding the above, it is not clear whether previous or current analyses (in the paper) have considered brick.
13. The bibliography should be expanded in terms of territory, ensuring that it is as up-to-date as possible.

Author Response

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Author Response File: Author Response.pdf