Natural Variability of the Color of Beech Wood in the Color Space CIE L*a*b*

Round 1

Reviewer 1 Report

1.     The significance, purpose and innovation of this research are supposed to be added in the Introduction.

2.     Line 75 How old the tress selected for the measurement? And please added Latin Name for the wood.

3.     Line89, due to the natural material properties of wood, the color distribution of each part is uneven. How do you determine the color selection site, or how do you reasonably determine the color space CIE L*a*b* values of sapwood, mature wood and false heartwood?

4.     Line 173, did you analyze the reason why the values of false heartwood on the lightness coordinate L* in Figure 3 is significantly lower than the other 2 bars?

5.     Line 173, the value on the yellow color b* vary little between sapwood, mature wood and false heartwood in Figure 3, did you consider why?

6.     Line 173, the analysis might have been more rigorous if an error bar had been added to Figure 2.

7.     Line 201/221/223, please adjust the format of the paragraphs.

8.     The growth sequence of sapwood, mature wood and false heartwood is sequential. Is there any significant law or the change rule of the color space CIE L*a*b* values?

9.     Try to explain the significance of the research results, such as the impact of the research results on the practical application of the relevant field.

10.   Please revise the format of the reference carefully.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

The topic is not new, neither in the case of beech nor in the case of colour space evaluation.

The chosen combination, both materials and methods, is not new.

The scientific merit and contribution in terms of new knowledge is thus almost none.

No advanced statistical methods were used.

The presentened conclusions are only mixture of figures. The applicability of such conclusions is very low and the benefits for the reader are also low.

The References contain a large amount of regional literature.

Author Response

I am attaching the answers to your questions in the file.

Author Response File: Author Response.docx

Reviewer 3 Report

The manuscript entitled ‘Natural variability of the color of beech wood in the color space CIE L*a*b*’ has interesting topic, because deep understanding in color formation and change of wood surfaces is not fully understood and controlled. The manuscript is well written, compact and gives very brief background information about the color of wood and its measurements. The author claims that the ‘natural color’ of beech was evaluated. As the author stated, the processing of wood affects its color and similarly all processes, also the process that the author used in wood material preparation affects the color starting from roughness, drying conditions, aging etc. The author also stated in the introduction that ‘The color of the wood is a basic physical-optical property…’ at the same time listing many chemical compounds of wood which could affect on color of wood, without mentioning any of these ‘physical’ properties for example roughness which affect light reflectance and therefore will also be the factor affecting the color of wood.

The author often talks about the color change (for example in the abstract and in the conclusions) ‘Within the framework of the categorization, the difference in wood color, the color difference between mature wood and sapwood belongs to the category of visible changes, and the difference in the color of the wood of the false heartwood from the color of the sapwood belongs to the category of significant color changes.’, however in most of the cases it should/might be the ‘color difference’ since the color of sapwood does not change during the study to mature or false heartwood color. They are just different color groups compared in this study.

These previously mentioned topics should be elaborated and addressed in the manuscript. In addition, there are some more specific recommendations:

page 7 line 242-245: The statement ‘The presented values of the natural color of dry sapwood beech, mature wood and false heartwood on the coordinates of the color space CIE L*a*b* are a source of information for determining the color of beech wood and in case of customer requirements, can be used to classify beech wood into classes according to color shades.’ should be rewritten because it is ambiguous. How and where it could be used in classification of beech for customers, if commonly beech wood is dried at elevated temperature, differently as in this study? As the authors discussed in introduction about drying at elevated temperature would end in different color.

page 2, line 77: The author states that ‘… healthy round false heartwood were selected…’. What is the definition for the ‘healthy’, if it is commonly known that the false heartwood is induced by different factors, including various kinds of injuries or stresses that damage the tree?

page 2, materials and methods: The author should describe the material and surface preparation process more specifically e.g., drying time, time from planing to color measurement, surface roughness and on which surface the measurements were done (rad, tan or longitudinal). How was the moisture content of wood measured? These are very important parameters affecting the results and would clarify the process and background to understand how the results were obtained.

Author Response

I am attaching the answers to your questions in the file.

Author Response File: Author Response.docx