Investigation towards Laser Cleaning of Corrosion Products from Lead Objects

Round 1

Reviewer 1 Report

This paper provides a detailed study of the corrosion mechanisms affecting land exposed to the environment. Likely mineral products are identified both as a result of interaction metallic lead with the environment and the deposition of unrelated atmospheric pollutants such as carbon deposits. As a result, it is valuable to anyone studying lead objects without a detailed knowledge of these processes.   The paper then examines the effects of laser cleaning when varying both laser intensity and pulse time. It provides the valuable information that the threshold of damage is lower for the lead than any of the corrosion products. An interesting array of analytical techniques are employed including scanning electron microscopy, Ramen spectroscopy and photoelectron spectroscopy all are well elucidated, and their value clearly illustrated.   The paper is well-written, and the conclusions are robust.   The principal question is how effective laser cleaning is to remove corrosion products from lead objects. The clear limitations of laser cleaning are well identified.  

The paper is usefully and informative as it stands.

 

Minor typos: line 198 one of THE fragments; line 236 I suggest: SEM was used for precise detection of the damage threshold.

XPS was used to examine the blue discoloration, why not the yellow.

Author Response

Dear Reviewer 1,

I followed all your recommendations (changes are highlighted yellow) and made language corrections in collaboration with my native English-speaker colleague (changes are highlighted grey).

As for your question, “XPS was used to examine the blue discoloration, why not the yellow”, in the case of blue color, the oxide layer was very thin, Raman and XRD did not see any signal from it. We used XPS because it examined only the thin layer.

In the case of possible yellowing, we have checked nearby layers with mechanical cleaning. We scratched with a scalpel the top-most dark dust/soot layer, and layers underneath were yellow. There was the same yellow as after laser irradiation. It gave us confidence that the color did not change from laser irradiation, just a black layer evaporated, revealing underneath anglesite. Therefore, we decided not to use XPS.

Kind regards,

Denis Prokuratov

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript “Investigation towards laser cleaning of corrosion products from lead objects” presents detailed results on the application of micro-, nano-, pico- and femtosecond pulsed lasers to clean atmospheric corrosion products from the fragments of 19th-century lead outdoor sculpture. The topic is well presented and the results are corroborated by the combined use of SEM imaging, reflectance and Raman spectroscopy. A deepened analysis on the effects of different duration of laser pulses is well presented. In my opinion, the manuscript is suitable for publication on Heritage after very minor revision:

 

-        The authors should add in the caption of figure 2b color details of the map presented. The same sentence of lines 152-153 is enough.

Author Response

Dear Reviewer 2,

I made all corrections according to all your recommendations (changes are highlighted green).

Kind regards,

Denis Prokuratov

Author Response File: Author Response.docx