The “Lost Guardians” of Dante’s Inferno: Medium Wave Infrared Imaging Investigations of a XIV Century Illuminated Manuscript

Round 1

Reviewer 1 Report

This work presents a technical examination of several pages and illuminations of a XIV century manuscript 221 of the Dante’s Divina Commedia (MS. 1102) preserved at the Biblioteca Angelica in Rome. The imaging methodology combined thermographic and reflectographic techniques.

I consider the paper need to be significantly improved.

Please, stress the novelty and the contribution of this wok in the imaging methodology, I do not find any outstanding point moreover the study of an ancient manuscript related to Dante’s Divina Commedia. You present only 4 images, in fact.

Do you have any technical information concerning the making of the document to support the suitability of the proposed imaging techniques?

Please, explain, the materials that are suitable to be detected with the proposed methods

Please, modify the figures in order to enlarge them, they are so small and difficult to observe.

Improve the quality of the images. Can you use any false color contrast?

How do you evaluate the deterioration conditions?

Can you tell something else about the well-preserved areas concerning the materials used in the manuscript or about the making of the illuminations?

Contrast and discuss the advantages of this examination versus other imaging methods or elemental mappings, for instance.  

Author Response

- Please, stress the novelty and the contribution of this work in the imaging methodology, I do not find any outstanding point moreover the study of an ancient manuscript related to Dante’s Divina Commedia. You present only 4 images, in fact

In the authors' intention, the manuscript is not only aimed at presenting a new imaging methodology but also at proposing its novel application  to  the study of illuminations. According to the Authors, given the importance of the artefact, the acquisition of any information and detail, though minimal, may contribute to gather a deeper knowledge of the artwork. In order to better highlight such an aspect, the novelty introduced by this work has been discussed in the introduction, lines 69-77: “Recently, a similar approach combining the use of PT and MIR has been successfully adopted for the study of painting on wood/canvas. Such an approach allowed us to obtain valuable information concerning the multiple layered structure of the artworks by revealing features buried beneath the visible pictorial layer and, in addition, by mapping the restorations and the stylistic changes [22-23].

In this work, the combined use of PT and MIR has been, for the first time, proposed for the investigation of illuminations. The results obtained on in the code MS. 1102 allowed to recover and/or improve the readability of some illuminations and to gather relevant information for the interpretation of the illumination iconography.”

Concerning the manuscript and the results, several information on the manuscript history have been added in section 2.1 lines 81-85: “This manuscript became part of the heritage of the Biblioteca Angelica thanks to the Cardinal Domenico Passionei, whose book collection was purchased by the Augustinians in 1762, after his death. The binding is that common to many volumes belonging to him: wooden axes, covered in leather decorated in gold, nerves and piece with gold title [2]. The text, arranged on two columns, was written by a single hand, which uses the Littera Textualis [2].”  and lines 94-97: “Unfortunately it is not possible to identify the name of the client of the work, that judging by the ambitious illustrative project can be assumed has been part of a very high social class, as it would seem to confirm also the abundant use of gold leaves that characterizes each illumination [2].”  

A new figure 1 has been added in order to give an example of the conservation state of the gildings.

 

-  Do you have any technical information concerning the making of the document to support the suitability of the proposed imaging techniques?

All the information reported in the literature has been added in section 2.1.

-Please, explain, the materials that are suitable to be detected with the proposed methods

The following sentence has been inserted in the introduction, lines 45-49: “Concerning cultural heritage investigations, these techniques were employed to analyse different kind of artefacts [5-8], enabling the study of both optically opaque samples, such as bronzes [9-12], and semi-transparent materials, like paintings [13-14] and manuscripts [15].” 

- Please, modify the figures in order to enlarge them, they are so small and difficult to observe. Improve the quality of the images. Can you use any false color contrast?

As indicated in the text the maximum camera resolution is 320x240 pixel (lines 128-130). However, in order to clearly display the highlighted details larger images have been inserted.

The software gives the possibility to use false colour contrast, but in the present case the details of interest appear more confused while, on the contrary, the black/white palette enables a clear visualization of the detected features.

- How do you evaluate the deterioration conditions?  Can you tell something else about the well-preserved areas concerning the materials used in the manuscript or about the making of the illuminations?

Some information on the state of deterioration have been inserted in section 2.1, lines 102-104: “The manuscript appears in a good state of conservation with few water stains and some hole due to woodworm attacks in part restored in 2008 (as attested from the manuscript digital catalogue Manus, link  https://manus.iccu.sbn.it/cnmd/0000304519).”

In this section also a series of information of the manuscript history, the illumination style and the client have been added.

 

- Contrast and discuss the advantages of this examination versus other imaging methods (irr) or elemental mappings, for instance. 

This aspect has been discussed at the end of the introduction, lines 56-68: “PT has proved to constitute a valuable tool for providing a general overview of the various elements composing illuminated manuscripts [18], being also able to provide information complementary to the ones that can be obtained by means of traditional techniques like the near-infrared reflectography. Moreover, it enables both the detection of underdrawings and the monitoring of the conservation state of the parchment support thus producing a unique reference documentation for directing further investigations, like compositional analysis and elemental mappings. On the other hand, MIR has been recently employed for the detection of possible underdrawings and graphical/pictorial features buried beneath different kind of paint layers [15,21].  It is worth noting that while PT enables a more effective detection of subsurface features when these are buried beneath highly MWIR diffusing layers, MIR can give complementary information on elements located beneath transparent layers the MWIR spectral range. Finally, unlike MIR, PT can provide in-formation about the depth of the detected feature.”

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper reports investigations on a very interesting object, although there are other techniques that can reveal the same or even more information. The methodology and the results are clearly presented, but they don't seem as revealing as the authors present them. Yes, you can get a clearer view, but an expert can identify the scenes as they are. Please find a better casuistic to present or change the point of view.

Author Response

-The paper reports investigations on a very interesting object, although there are other techniques that can reveal the same or even more information.

 The approach proposed by the authors is based on previous studies [18, 22-23]  where different techniques able to provide complementary results have been adopted, thus allowing  more accurate in-depth studies of the artworks in comparison with the ones carried out by means of a single technique. 

To better outline such an aspect, the following modification has been introduced in the text as reported in the introduction (lines 56-68): “PT has proved to constitute a valuable tool for providing a general overview of the various elements composing illuminated manuscripts [18], being also able to provide information complementary to the ones that can be obtained by means of traditional techniques like the near-infrared reflectography. Moreover, it enables both the detection of underdrawings and the monitoring of the conservation state of the parchment support thus producing a unique reference documentation for directing other further investigations, like compositional analysis and elemental mappings. On the other hand, MIR has been recently employed for the detection of possible underdrawings and graphical/pictorial features buried beneath different kind of paint layers [15,21].  It is worth noting that while PT enables a more effective detection of subsurface features when these are buried beneath highly MWIR diffusing layers, MIR can give complementary information on elements located beneath transparent layers in the MWIR spectral range. Finally, unlike MIR, PT can provide information about the depth of the detected feature.”

-The methodology and the results are clearly presented, but they don't seem as revealing as the authors present them. Yes, you can get a clearer view, but an expert can identify the scenes as they are. Please find a better casuistic to present or change the point of view.

The spectrum of results has been expanded (see the new figure 1) and the discussion extended at several points in the manuscript (see the introduction and the section 2.1) to make the case study approach the paper intends to propose, more sound. However, considering the relevance of the manuscript, the present article is a case report aimed at providing further information for the interpretation and, in general for the artistic study of the illuminations that can be extremely useful for scholars. For example, some details, like the tree branches shown in Fig. 3 or the physiognomic traits of the demon in figure 5, could constitute a significant support for both the artistic attribution and the stylistic analysis of the illuminations.

Author Response File: Author Response.pdf

Reviewer 3 Report

The paper of Orazi et al. is an interesting case study that investigates several illuminations of a very important 14^th c. manuscript via imaging techniques operating in the medium wave infrared range. The paper is clearly written and overall has a nice flow when reading it. The obtained results highlight exciting details of the original iconography, otherwise not visible to the naked eye due to severe deterioration. Besides the high relevance of the investigated object, the paper shows also the potential of thermographic and reflectographic techniques for the study of illuminations found in a precarious state of preservation.

I have only some minor comments and suggestions for the authors, as indicated below:

Lines 30-31: "The latter is considered the most famous Italian literature work and it is also the most studied and commented poetic-literary text in the world." Please add a reference to sustain this claim.

Line 32: "the code MS. 1102 assumes an exceptional relevance…". When first introducing the manuscript MS. 1102 please provide more details in order for the reader to clearly understand the context/what object is investigated.   

Line 50-56: I recommend to revise this part of the text and better highlight the advantages of each technique. The text is a bit confusing. If PT can also detect underdrawings (as stated) why also use MIR. Please clarify. Also, are there any potential risks to works of art by using such techniqyes (cumulative heating? I suggest to the authors to address within their discussion also this point and include some references in this regard.

Section 2.1 It would be nice if the authors could include a brief discussion of any previous investigations carried over time on this important manuscript. It would create a richer context/background of the present study.

Section 2.2. No details are provided in terms of data processing or any of the software used in this regard. Some clarifications are required.

Results

Lines 102-103: "The PT analysis has been performed on all the thirty-four illuminations of manuscript MS. 1102 in order to evaluate the conservation state of the gildings..". Why did the authors not include some of the results obtained on this subject? It would enrich the manuscript.

Lines 102-111: Please clearly specify in the text that only the results obtained on the damaged folios will be included and discussed in the manuscript. As it is now, the text is not very clear for the reader.

Figures (in general). I strongly recommend to include much larger images (with best resolution) in order for the reader to clearly see/study the highlighted details.

Lines 209-212: I suggest to the authors to include also some remarks on the limitations of the applied methodology in this particular case.

Lines 213-218: The fact that extended damage were found only in areas where demoniac figures are represented in very interesting. I assume that the manuscript has a well know documentation. Are there any clue on when these (most probably induced) damages may have happened? It would be great if the authors could extend this part with a bit more details, if possible.

Author Response

-Lines 30-31: "The latter is considered the most famous Italian literature work and it is also the most studied and commented poetic-literary text in the world." Please add a reference to sustain this claim.

The sentence has been changed to: “The latter is considered one of the most famous Italian literature works and it is also one of the most studied poetic-literary text” and, in this respect, the following reference has been added Favaro, M. (2017). Dante da una prospettiva friulana: sulla fortuna della Divina Commedia in Friuli dal Risorgimento ad oggi. Dante da una prospettiva friulana, 1-167.

-Line 32: "the code MS. 1102 assumes an exceptional relevance…". When first introducing the manuscript MS. 1102 please provide more details in order for the reader to clearly understand the context/what object is investigated.

More details have been added in section 2.1, concerning the history of the manuscript, see the introduction at lines 81-86 : “This manuscript became part of the heritage of the Biblioteca Angelica thanks to the Cardinal Domenico Passionei, whose book collection was purchased by the Augustinians in 1762, after his death. The binding is that common to many volumes belonging to him: wooden axes, covered in leather decorated in gold, nerves and piece with gold title [2]. The text, arranged on two columns, was written by a single hand, which uses the Littera Textualis [2].”  and lines 94-97: “Unfortunately it is not possible to identify the name of the client of the work, that judging by the ambitious illustrative project can be assumed has been part of a very high social class, as it would seem to confirm also the abundant use of gold leaves that characterizes each illumination [2].”  

- Line 50-56: I recommend to revise this part of the text and better highlight the advantages of each technique. The text is a bit confusing. If PT can also detect underdrawings (as stated) why also use MIR. 

The sentence has been changed (introduction lines 56-73): “PT has proved to constitute a valuable tool for providing a general overview of the various elements composing illuminated manuscripts [18], being also able to provide information complementary to the ones that can be obtained by means of traditional techniques like the near-infrared reflectography. Moreover, it enables both the detection of underdrawings and the monitoring of the conservation state of the parchment support thus producing a unique reference documentation for directing other further investigations, like compositional analysis and elemental mappings. On the other hand, MIR has been recently employed for the detection of possible underdrawings and graphical/pictorial features buried beneath different kind of paint layers [15,21].  It is worth noting that while PT enables a more effective detection of subsurface features when these are buried beneath highly MWIR diffusing layers, MIR can give complementary information on elements located beneath transparent layers in the MWIR spectral range. Finally, unlike MIR, PT can provide in-formation about the depth of the detected feature.”

Recently, a similar approach consisting in the combined use of PT and MIR has been successfully adopted for the study of painting on wood/canvas where theseanalysis allowed to obtain extensive information concerning the multiple layered structure of the artworks by revealing features buried beneath the visible pictorial layer and by mapping the restorations and the stylistic changes [22-23].”

 

- Please clarify. Also, are there any potential risks to works of art by using such techniques (cumulative heating? I suggest to the authors to address within their discussion also this point and include some references in this regard.

The following sentence has been added in section 2.2 lines 117-120: “The employed pulse power was around 20% of the maximum one, thus producing a temperature rise of less than 10 °C, that can be then considered low enough so as to not irreversible modifications in the investigated artifacts [18].” Reference n. 18 has been also inserted in the text.

- Section 2.1 It would be nice if the authors could include a brief discussion of any previous investigations carried over time on this important manuscript. It would create a richer context/background of the present study

Unfortunately, to the best of our knowledge there have not been previous investigations carried out on the manuscript. The Manus catalogue (https://manus.iccu.sbn.it/cnmd/0000304519) reports only on a restoration made in 2008 as mentioned  in section 2.1,  lines 102-104: “The manuscript appears in a good state of conservation with few water stains and some hole due to woodworm attacks in part restored in 2008 (as attested from the manuscript digital catalogue Manus, link  https://manus.iccu.sbn.it/cnmd/0000304519).”

- Section 2.2. No details are provided in terms of data processing or any of the software used in this regard. Some clarifications are required.

Further details have been added in section 2.2, lines 130-134: “The Altair 5.50 software was used to process the images collected in full frame mode with a 150 Hz frame rate. To obtain the time dependent change of the thermographic signal to start from the zero level in all the pixels, a pixel by pixel subtraction of the frame obtained just before the flash pulse from the sequence of the thermograms has been performed.”

- Lines 102-103: "The PT analysis has been performed on all the thirty-four illuminations of manuscript MS. 1102 in order to evaluate the conservation state of the gildings.". Why did the authors not include some of the results obtained on this subject? It would enrich the manuscript.

As an example of the gildings state of conservation a new fig. 1 has been inserted in the manuscript.

- Lines 102-111: Please clearly specify in the text that only the results obtained on the damaged folios will be included and discussed in the manuscript. As it is now, the text is not very clear for the reader.

The text has been changed to: “Hereafter, only the results obtained on the four damaged illuminations containing the representations of the demoniac guardians, which appear barely detectable in the ordinary pictures, will be shown.”

- Figures (in general). I strongly recommend to include much larger images (with best resolution) in order for the reader to clearly see/study the highlighted details.

As indicated in the text the maximum camera resolution is 320x240 pixel (lines 128-129). However, in order to clearly display the highlighted details larger images have been inserted.

- Lines 209-212: I suggest to the authors to include also some remarks on the limitations of the applied methodology in this particular case.

The limitation is mainly due to the loss of the pictorial layer, in the text the following sentence has been added (lines 309-311): “This is probably due to the in depth extended damage, that caused the completely lack of the pictorial layer.”

-Lines 213-218: The fact that extended damage were found only in areas where demoniac figures are represented in very interesting. I assume that the manuscript has a well know documentation. Are there any clue on when these (most probably induced) damages may have happened? It would be great if the authors could extend this part with a bit more details, if possible.

Unfortunately, the damage is not documented. It has been reported for the first time only on the reference n. 2 (Medica, M.; Illuminati, C., Terlizzi, F. La Divina Commedia. Manoscritto 1102 della Biblioteca Angelica di Roma. Commentarii all’edizione facsimile; Imago: Rimini, Italy, 2017)

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Most of the recommendations were addressed. The paper was improved.

Reviewer 2 Report

The paper reports investigations on a very interesting object.