Life Cycle Assessment of Proofing Test Production on Printing Surfaces with Use of Carbon Footprint Methodology

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript describes to quantify the impact of of proof printing on the environment through LCA analysis. The abstract is clearly written and section introduction gives background for the research, however, section Introduction lacks additional data about the proof-printing significance in the whole printing process. How often proof-printing is done, what input is made to reach proof-printing, what if a mistake happens and proof-printing fails to remove errors from the final print process. How important is the proof-printing process in a whole picture of printing. What % of printing LCA could be assumed for proof-printing.

Section 2 partly covers previously addressed questions, but additional clarification is needed.

Figure 3 describes system boundary for the LCA proofing process. How does proof-printing differs from trial printing? What amount of printed specimens are reached?

Why trial printing is considered as a waste (output).

In section 2, was any recycling options considered in the LCA? PE plastic films can be recycled, does it contribute to the reduction of GHG emissions and overall LCA process and the results?

Table 1. Why 400km of transportation considered?

 

 

Conclusions. Conclusions are based on the obtained results. Two various proofing systems were compared. It is concluded that there is a 20-fold reduction in climate emissions using the proofing system on the target substrate. However, does the both methods comply with the ISO standards mentioned in the text. What drawbacks can be from the application of the proposed proofing system? If one mistake costs whole printing batch failure due to different testing system, the results from proofing benefits could be much worse. On the other hand, if authors propose and justify why the method outperforms traditional one, can we conclude that current ISO standard is too conservative for new technologies in printing?

Author Response

Comments 1: The manuscript describes to quantify the impact of of proof printing on the environment through LCA analysis. The abstract is clearly written and section introduction gives background for the research, however, section Introduction lacks additional data about the proof-printing significance in the whole printing process. How often proof-printing is done, what input is made to reach proof-printing, what if a mistake happens and proof-printing fails to remove errors from the final print process. How important is the proof-printing process in a whole picture of printing. What % of printing LCA could be assumed for proof-printing.

Response 1: Proof printing represents an environmentally sustainable and economically advantageous method for presenting graphic designs during the graphic design stage or after completing a rebranding project. In this study, proof printing was conducted for each design described and is considered a standard proofing system with the added advantage of being performed on the target substrate. This method allows for the inclusion of selective white separation and the actual print finish, such as matte varnish. Trial printing is only performed prior to proof printing in cases involving complex graphic designs that feature intricate graphic elements. For proof printing, the input data are consistent with those used in conventional proofing or trial printing. The following elements are utilized during the process: print-ready files in the form of a single-use layout, machine profiles (dedicated profiles for flexographic or rotogravure technologies, or the standard ISO PSO profile for offset printing in most cases), parameters of special colors represented by spectral data or LAB values, colorimetric data for CMYK process colors derived from the machine profile, white ink opacity (if applicable), and varnish matte levels (if applicable).

Challenges in proof printing do not arise due to the established method for correctly preparing files for printing. For particularly complex graphic elements, trial printing is utilized, which in this study is performed for every 20th job. Proof printing represents the culmination of technological work on a design, integrating the developed solutions into the final product. It is particularly effective during rebranding processes, where changes to graphic layouts are required, such as removing the white underprint from packaging printed on metallized foil to achieve a premiumized metallic background effect, or showcasing transparent elements and special effects like selective matte varnish on glossy foil. Before the adoption of the proof-printing system, clients who wanted to visualize such changes were required to perform a printing test in a production environment, which involved considerable time, material, and financial costs. The implementation of proof printing significantly reduces these burdens.

Proof printing is a critical step in both the prepress process and the subsequent stages of the printing process. Proofing on the target substrate is a proofing system in the full sense of the term, certified under the ISO 12647-7:2016 standard (Graphic technology — Process control for the production of halftone colour separations, proof and production prints, Part 7: Proofing processes working directly from digital data). This system forms the basis for customer approval of graphic designs, color scheme determination, and machine verification during production. By comparing the proof to the printing output, discrepancies in color reproduction can highlight issues such as inconsistencies in machine settings, incorrect file preparation, or flawed printing forms, although the latter two are extremely rare.

Regarding the Life Cycle Assessment (LCA) distribution between proof printing and commercial printing, it is not feasible to determine a precise percentage based solely on general data. A detailed calculation would require the total resource consumption (e.g., raw materials, water, electricity, and waste) for commercial printing to be determined. The LCA share will vary significantly depending on the type of packaging material—monomaterials with reverse printing (e.g., water labels) or surface printing sealed with varnish (e.g., frozen food bags made from LDPE white) compared to multi-material laminates (e.g., OPP matte + OPP metallized). To accurately quantify the LCA percentage share of proof printing within a commercial printing project, it would be necessary to analyze a representative order from the scenarios mentioned above. Nonetheless, the percentage difference in LCA for proof printing vs. commercial printing can be approximated based on the data presented in this study, where trial printing is measured at 0.017 kg PE and proof printing at 800 kg PE, yielding a difference of approximately 0.021%.

Comments 2: Section 2 partly covers previously addressed questions, but additional clarification is needed. Figure 3 describes system boundary for the LCA proofing process. How does proof-printing differs from trial printing? What amount of printed specimens are reached?

Response 2: In the case of proof printing, the process involves a system based on the presentation of a certified contract proof that reflects the appearance of the final commercial print using the target substrate and established colorimetric data. At this stage, proof printing demonstrates all the technical aspects of the commercial print, including the machine profile and the specifications for preparing files for printing. Proof printing represents the final stage of file preparation for printing and serves as a color reference during the acceptance process in commercial printing.

The scenario differs slightly for trial printing, which is conducted as a test to resolve challenges in the construction of complex graphic elements that cannot be accurately reproduced through proof printing due to technological limitations. In rebranding projects involving technically intricate print elements sensitive to printing process conditions, trial printing becomes essential to evaluate and select the optimal version from the proposed solutions. The selected version is then implemented into the proof-printing process. This approach ensures that the proof-printing system can function effectively in the subsequent stages of preparing derivative designs.

Comments 3: Why trial printing is considered as a waste (output).

Response 3: As detailed above, trial printing is used to test challenging graphic elements during the printing process. This testing typically involves multiple repetitions of the same graphic element, constructed in various ways, to determine the optimal solution. The layout used in trial printing does not include the full graphic design, as the testing is conducted at the stage of reprographic processing of the design. Consequently, all components of the trial printing process -such as graphic files, printed foil, photopolymer plates, and printing inks - are classified as waste.

Comments 4: In section 2, was any recycling options considered in the LCA? PE plastic films can be recycled, does it contribute to the reduction of GHG emissions and overall LCA process and the results?

Response 4: The subject of the research and article was to determine the LCA (Life Cycle Assessment) for printing production based on the proofing system on the target substrate and production testing. The studies focused on the advantages of the proofing system on the target substrate, including reductions in waste, water consumption, raw materials, and electricity, compared to the conventional method of machine testing. While determining the recycling amounts and their impact on the carbon footprint was not the primary objective of the research, related data emerged during the study but were not fully developed.

Nevertheless, in the case of trial printing, all printed raw materials, totaling 800 kg, were recycled by reprocessing them as an additive in foil production. For the raw materials used in the proofing process on the target substrate, totaling 0.017 kg, the waste was neutralized through combustion at a waste incineration plant with partial energy recovery. Due to the proprietary process of preparing proofs on the target substrate, which is a Chespa's proprietary intellectual technology, the proofs produced using this method cannot be recycled.

Comments 5: Table 1. Why 400km of transportation considered?

Response 5: In Chapter 4, Modeling, Table 1 presents a transport distance of 400 km. This includes the transport of raw materials to the printing house, estimated at 300 km for the project examined in Section 4.1, and the distance the customer must travel from their office to the printing house to participate in the printing and acceptance process, estimated at 100 km as described in Section 4.2. For calculating the LCA of the printing process, transport was considered crucial due to its impact on the emission of volatile compounds into the atmosphere.

Comments 6: Conclusions. Conclusions are based on the obtained results. Two various proofing systems were compared. It is concluded that there is a 20-fold reduction in climate emissions using the proofing system on the target substrate. However, does the both methods comply with the ISO standards mentioned in the text.

Response 6: To discuss ISO standards in flexography, it is essential to explain their purpose and how they function. The rules differ slightly from those of offset printing, where the ISO PSO standard is mandatory and defines the parameters and requirements for inks and printing processes to ensure compliance with ISO standards.

In flexographic printing, however, ISO standards serve as guidelines for the printing industry rather than mandatory rules, as is the case in offset printing.

Trial printing is conducted based on the processing of graphic files using technical data provided by the Print Management Agency. This includes specifications for file preparation during the artwork stage, followed by image retouching and reprographic processing linked to a machine profile. The machine profile is developed through the printing of a Fingerprint test. It forms the foundation for verifying the accuracy of printing and machine settings during a printing test. At this stage, the solutions are validated using technical information from the printing house, including the preparation of printing forms.

In proof printing, each contract proof must be prepared in accordance with the ISO 12647-7:2016 standard (Graphic Technology — Process Control for the Production of Halftone Color Separations, Proof and Production Prints, Part 7: Proofing Processes Working Directly From Digital Data). Adherence to this standard is necessary for the proof to be considered consistent. The correct preparation and printing of a contract proof result in its certification according to the aforementioned standard. Certification is conducted using programs such as GMG COLOR PROOF Control, which create a job containing the color profile of the printing machine and ensuring compliance with ISO 12647-7:2016.

In conclusion, both trial printing and proof printing align with the applicable standards and principles for producing contract proofs and commercial prints, ensuring consistency and quality throughout the printing process.

Comments 7: What drawbacks can be from the application of the proposed proofing system?

Response 7: The Proof-Printing system, like any digital printing technology, has its limitations, particularly when target printing tools are not used. However, thanks to the machine profile, which defines numerous printing parameters—such as spectral values of process and spot colors, white ink opacity, substrate, type of finish, matte level of varnish, and raster tone value—it is possible to reproduce information on the proof on the target substrate with very high accuracy, as evidenced by the certification report.

It is important to note that every proofing system is based on digital technology and adheres to ISO standards, which define permissible deviations for contract proofs to achieve certification. These standards allow for mathematical and visual variations within specified tolerances. Additionally, as previously described, when projects contain complex and technically challenging elements, a Trial Printing test is required. The results of this test are subsequently translated into proofing on the target substrate.

To summarize, the most significant limitation of the described system, as well as any proofing system based on digital printing, lies in the simulation of special colors in bitmaps. Special colors in printing are achieved using specific pigments. For example, the color PMS 2430 C is derived from pigments such as PMS Yellow PY12, PMS Rubine Red, PMS Black, and PMS Transparent White. In contrast, the simulation of this color in digital printing involves a combination of 10 available inks. As a result, the spectral characteristics of a given color in commercial printing and proofing printing will differ.

Comments 8: If one mistake costs whole printing batch failure due to different testing system, the results from proofing benefits could be much worse. On the other hand, if authors propose and justify why the method outperforms traditional one, can we conclude that current ISO standard is too conservative for new technologies in printing?

Response 8: The primary reason for the rejection of input production often stems from graphic errors caused by improper preparation of graphic elements. The proofing system on the target substrate significantly mitigates and eliminates such issues. By enabling the preparation of proofs on metallized or transparent substrates, it allows for quick and precise verification of whether a specific graphic element has been prepared correctly. For instance, it ensures that a design includes or excludes a white ink underlayer, has the correct trapping or grip, and so forth. Standard proofing systems, which rely on white paper (glossy, semi-matte, or matte), lack this capability due to technological limitations.

After producing a proof on the target substrate, both the graphic designer and the customer can see the actual design as it will appear in commercial printing, with all technical aspects intact. If the customer rejects an element in the proof, for example, a chosen color such as PMS 101 printed directly on aluminum that turns greenish and deviates from expectations, the proof can be rejected. The customer can provide feedback to select a better-matching color. This process demonstrates the undeniable advantages of proofing on the target substrate over conventional proofing systems on white paper, avoiding costly rework or production delays when commercial approvals are conducted.

The proofing system on the target substrate adheres to ISO standards for proofing and incorporates machine profiles, ensuring that the proofs meet the highest quality requirements. For particularly challenging and complex projects, trial printing is essential to predict the behavior of inks, photopolymer plates, or graphic designs on the printing machine—factors that digital proofs cannot reliably determine. Proofing on the target substrate also plays a crucial role in the flow of information and provides a physical representation for the final client, i.e., the brand owner, of how their design will look long before photopolymer plates are produced or production begins.

Most marketing departments of leading packaging companies lack the knowledge and experience in printing technology to visualize how their designs will appear in production. A critical issue is that creative agencies often present clients with project proofs on perfect white, glossy proofing paper, often with pastel colors and selective white ink. In contrast, the actual printing will be on aluminum foil, finished with matte varnish at a gloss level of 10 GU (measured by a BYK GmbH glossmeter). The proofing system on the target substrate has revolutionized the market by offering brand owners the ability to assess the actual appearance of their packaging long before production. This system eliminates the need for trial printing for every design within a family of designs, resulting in significant savings of time and money while reducing environmental emissions.

Reviewer 2 Report

Comments and Suggestions for Authors

This study assesses the environmental impacts and eco-efficiency of proof printing using the life cycle assessment (LCA) methodology. While the work is commendable, there are a few minor issues that need to be addressed:

1. Please compare the findings of this study with existing literature and clearly highlight its contributions. This will better contextualize the work within the broader research landscape and underscore its novelty.
2. Please clarify all figure captions, particularly starting from Figure 4. Captions should be self-explanatory and provide sufficient context for the reader to understand the figure independently.
3. In the introduction section, please define “DTP”.
4. There are discrepancies in the section numbering in Parts 3 and 5. For example: "2.2. Data" "3.4. Sensitivity analysis".

 

 

Author Response

Comments 1: Please compare the findings of this study with existing literature and clearly highlight its contributions. This will better contextualize the work within the broader research landscape and underscore its novelty.

Response 1: To the best of our knowledge, there have been no prior studies, analyses, or publications of this kind – ours is the first.

Before the development of the proofing system in Chespa, there was no such system existed. This was confirmed by GMG Color, the software producer for proofing, which expressed interest in acquiring this technology to offer it to their clients.

As a result – and comparing to the above – we are unable to provide any examples of similar systems. The Kodak Approval system used substrates dedicated to its technology and was not certifiable. While we had access to this system, it primarily produced "prints" rather than proofs. However, at that time, it was the only technology capable of demonstrating transparency or metallic effects in a design.

There is only one example from the book Poligrafia; sztuka, techniki, technologia, published by COBRPP in 2021 (in Polish), authored by a team including Blachowski K. and others.

Comments 2: Please clarify all figure captions, particularly starting from Figure 4. Captions should be self-explanatory and provide sufficient context for the reader to understand the figure independently.

Response 2: Thank you for bringing the typos to our attention. We have carefully reviewed and corrected them. The updated manuscript will be submitted soon.

Comments 3: In the introduction section, please define “DTP”.

Response 3: Thank you for your valuable feedback. We appreciate your suggestion and will ensure that the definition of “DTP” is added to the introduction section for clarity.
For your consideration, a DTP operator (Desktop Publishing operator) is a skilled professional responsible for preparing and formatting text, images, and graphics into a final layout suitable for printing or digital publishing. In the printing industry, their role typically involves file preparation, software use, layout adjustments, proofing, prepress coordination, and quality assurance.

Comments 4: There are discrepancies in the section numbering in Parts 3 and 5. For example: "2.2. Data" "3.4. Sensitivity analysis".

Response 4: Thank you again for bringing the typos to our attention. All typos were carefully reviewed and corrected, and the updated manuscript will be submitted accordingly.

Reviewer 3 Report

Comments and Suggestions for Authors

I think the title is wrong, it is just wrong to juxtapose the word Life Cycle Assessment, analysis and carbon footprint. Life Cycle Assessment analysis using the carbon footprint. LCA is an analysis in itself, and CF is different from LCA.

I don't quite understand the description of the case study. The case study should be a research method used, in the context of complex issues, to extend experience or reinforce what is already known from previous research. However, the description of your case study is not very clear, it is not clear why it could contribute to extending experience, why it was chosen and what discovery it could lead to.

The choice of FU should be justified, because it seems to fall from the sky.

With what software did you calculate the impacts? The description of the inventory phase is completely missing (it is a mere Table) as well as the Life Cycle Impact Assessment phase. What calculation methodology did you choose and why only that?

But the thing that puzzles me the most is why, of so many impact categories, you have chosen only so few (missing are so many impacts related for example to other atmospheric categories such as SO2, CFC, Nox) as well as all the other categories typical of a midpoint.

In addition, a comparison with other literature studies is totally absent.

Author Response

Comments 1: I think the title is wrong, it is just wrong to juxtapose the word Life Cycle Assessment, analysis and carbon footprint. Life Cycle Assessment analysis using the carbon footprint. LCA is an analysis in itself, and CF is different from LCA.

Response 1: Thank you for pointing that out - it’s an excellent observation. We appreciate your clarification about the distinction between Life Cycle Assessment (LCA) and carbon footprint (CF). Based on your feedback, we have updated the title to better reflect the relationship and ensure accuracy.

The updated title is "Life Cycle Assessment of Proofing Test Production on Printing Surfaces with Use of Carbon Footprint Methodology" - and will be changed in the updated version of the manuscript. We hope the revised title aligns with the intent and structure of the work. Your input has been invaluable, and we’re grateful for your expertise in helping us refine our approach.

LCA (Life Cycle Assessment) and PCFP (Product Carbon Footprint) are closely connected, as both methodologies focus on assessing the environmental impacts of a product, system, or service. However, they differ in scope, purpose, and detail. Both methods can successfully overlap and complement each other, or depending on the research scope, they can be separate research cores. In the case of this article and research, both methods were considered as equivalent for the conducted analyses. Not only the equivalents for greenhouse gas emissions were calculated - in the scope of PCFP, but also the toxicological impact on the biosphere - in the scope of LCA.

LCA is the Foundation for PCFP, because LCA provides the framework: LCA is a comprehensive methodology used to evaluate the environmental impacts of a product or system throughout its entire life cycle, from raw material extraction (cradle) to disposal or recycling (grave). This includes impacts such as energy use, water consumption, emissions, and waste generation. PCFP focuses on carbon emissions: A PCFP is a subset of an LCA. It specifically calculates the greenhouse gas (GHG) emissions associated with a product across its life cycle, expressed as carbon dioxide equivalents (CO₂e). It uses the same life cycle stages and data as LCA but narrows the focus to climate change impacts.

Both LCA and PCFP analyze the same life cycle stages, including: raw material extraction, manufacturing and Production, transportation and distribution, use phase, end-of-life (recycling or disposal). For a PCFP, the calculation zeroes in on GHG emissions at each stage, whereas a full LCA may consider additional impact categories like water pollution, land use, or resource depletion.

Both methodologies LCA and PCFP are guided by ISO standards, ensuring consistency and credibility. LCA typically follows ISO 14040, and ISO 14044, while PCFP calculations often adhere to ISO 14067 or GHG Protocol Product Standard. Both calculation processes require detailed data collection for inputs, outputs, and processes throughout the product life cycle.

PCFP methodology focuses exclusively on GHG emissions (climate change), making it less complex to communicate to consumers. Easier decision-making: PCFP is often used by companies for carbon labelling, reporting, or setting decarbonization goals. LCA, being broader, is better suited for comprehensive environmental impact assessments.

The Chespa proofing on target substrate aims to reduce the impact of the printing process on the natural environment, taking into account as many pollutants as possible, including; greenhouse gas emissions, water consumption, electricity, waste production, recycling, waste disposal, and aspects of aquatic toxicology and the biosphere. In this study, both methodologies are closely linked and form a harmonious organism. We used LCA for environmental impact assessments, eco-design, sustainable product development, and policy-making. The Carbon footprint labeling was used for; climate action strategies, carbon neutrality claims, and compliance with GHG reporting regulations.

Comments 2: I don't quite understand the description of the case study. The case study should be a research method used, in the context of complex issues, to extend experience or reinforce what is already known from previous research. However, the description of your case study is not very clear, it is not clear why it could contribute to extending experience, why it was chosen and what discovery it could lead to.

Response 2: The case study describes the situation of empirical experiences of the Chespa company, which cooperates with brand owners in the field of preparing graphic files for printing in the ready-to-print format. The described case is only one situation when the brand owner accepted the graphic on the paper proof, went to the printing house for acceptance, and also accepted the graphic on the print, which he placed on white proofing paper, where the visual convergence of the paper proof to the print was almost 100%. However, after this acceptance, the brand owner cut one label from the foil sheet and wrapped the bottle with the brown drink, as can be seen in Figure 2. As it turned out, several graphic elements significantly changed their shade and perception; the lemon became flat and dirty, the yellow stripe became darker, and the brown Pantone raster behind the word "tea" merged with the color of the liquid in the bottle. After this test, the brand owner rejected the project, ultimately not accepting the printout. The lack of acceptance resulted in a decrease in the work from the machine and; disposal of several thousand meters of OPP TREOFAN transparent of high material value, consumption of printing inks, consumption of water, electricity, chemicals for washing the printing machine, and printing tools, disposal of photopolymer plates, transport of materials to the printing house, travel of the brand owner to the printing house, and consequently the necessity to perform the reprographic work from the beginning, i.e. further losses; time, electricity, water, greenhouse gas emissions, etc. In addition, the brand owner was not able to determine what and how to improve, he wanted it to be "nice". The main objection was that there is no method on the market for showing certified proof on the target substrate. This was the moment when Chespa decided to develop such a system. There were many examples of this type among other brand owners; the influence of brown kraft liner on the colors and the problem of visual assessment of the sample due to aspects of color physics, the difficulty of assessing graphic elements without under printed with white ink or selective white ink on metalized substrates, assessment of graphics on GD2 waste cardboard vs. on GC1 primary cardboard, simulation of special effects such as; selective matt/gloss varnish or simulation of cold stamping or hot stamping.

In the case of the described problem, the research method is the influence of the brand owner's decision-making process on the design acceptance process based on the best available data and materials, allowing for a faithful evaluation of the graphic before the commercial printing process.

At the time of the development of the Chespa system for proofing on the target substrate, to the best of our knowledge and information from the market, there was no certified proof system using production substrates. A leading software manufacturer confirmed this on the European market, who also worked on the development of such technology. Also one of the leading, global printers of flexible materials, after analyzing Chespa's proofs, stated that our solution works and is the only certified system for proofing on the target substrate that they have encountered globally.

After implementing the proofing technology on the target substrate, the process was completed during the introduction of corrections to the above-described label, the brand owner did not have to guess and guess what his product might look like on the shelf, he received a ready label on the target substrate long before printing, when there was an almost non-invasive possibility of introducing corrections to the project. The system allowed for a drastic reduction of costs, e.g. by reducing or eliminating the need to conduct machine tests or offloading work from the printing machine.

Comments 3: The choice of FU should be justified, because it seems to fall from the sky.

Response 3: In Life Cycle Assessment (LCA), the functional unit is a fundamental concept that provides a standardized basis for comparing products, processes, or systems. It is a quantified reference point that defines the function or service provided by a product or system and is used to ensure fair and meaningful comparisons of environmental impacts.

To speak of an actual functional unit, it must correspond to the subject of the study; and have to be clearly measurable and expressed in terms of numbers (e.g., 1 megawatt-hour of electricity, 1 kg of component), focused on the actual function or service delivered by the product or system, used uniformly throughout the LCA to maintain the integrity of the analysis.

Comparing both processes using a functional unit concerning the study objectives, a functional unit is defined as the end of the process of preparing a pattern for commercial production concerning the conventional system compared to the Chespa system, to account for differences in substrate, water, electricity consumption, and GHG emissions.

Comments 4: With what software did you calculate the impacts? The description of the inventory phase is completely missing (it is a mere Table) as well as the Life Cycle Impact Assessment phase. What calculation methodology did you choose and why only that?

Response 4: The calculations were carried out using the Climate3-LCA software. This software is based on the calculation principles of ERP systems with connected databases such as ecoinvent 3.8, Gemis 5.0 and others. The Climate3-LCA framework has been developed since 2009 and has already been used in over a hundred PCF/LCAs. A special feature of Climate3-LCA is its integration into ERP systems. This enables real in-line eco-control.

Corsus Sustainability Hamburg critically reviewed the software, which was also checked and published in Germany by the Umweltgutachterausschuss at the Federal Ministry for the Environment, Nature Conservation, Nuclear Safety, and Consumer Protection.

This LCA/PCF calculation method enables very in-depth calculations with complete LCA analyses taking into account more than 15 types of environmental impacts such as acidification, various ecotoxicities (Biodiversity), water scarcity, land use

Comments 5: But the thing that puzzles me the most is why, of so many impact categories, you have chosen only so few (missing are so many impacts related for example to other atmospheric categories such as SO2, CFC, Nox) as well as all the other categories typical of a midpoint.

Response 5: The environmental impact covered by the project described in the article was intended to present mainly the emission of greenhouse gases into the atmosphere. This compound was also described since one of the main greenhouse gases is carbon dioxide. In addition, the proofing system on the target substrate is primarily intended to reduce the generation of waste at the pre-production stage. Also, it serves to reduce the consumption of water, electricity, human resources, working time and costs. The topic of plastic pollution and, above all, microplastics and nanoplastics prompted the authors to focus on the indicated aspects of this study. It was decided not to fully take into account aspects of toxicology and contamination with other chemical compounds such as sulphates, nitrates and other compounds including organic chemicals such as trichlorofluoromethane.

The full LCA assessment that was performed for the example in question includes extended data with parameters such as; Acidification [KG SO2-Eq.], Eutrophication [KG PO4-Eq], Abiotic Resource Consumption [KG Antimony Eq], Stratospherical ozone depletion [KG CFC-11-Eq], Terrestrial Ecotoxicity [KG 1.4-DCB-Eq].

It is the authors who determine the scope of data that will be used in the publication, assessing its relevance to the given study and application in the industry, in this case, packaging, packaging market and waste management regulations including Packaging and Packaging Waste Regulation (PPWR).

Comments 6: In addition, a comparison with other literature studies is totally absent.

Response 6: Thank you for your observation regarding the absence of a comparison with other literature studies. We acknowledge that this aspect requires further elaboration to strengthen the contextual relevance of our findings.

In response, we have reviewed additional studies that align with the focus of our work, particularly those assessing environmental impacts and sustainability in the printing industry using the Life Cycle Assessment (LCA) methodology. 

Our study contributes to the growing body of research on the environmental impacts of printing processes. For instance, the study by Keys et al. (2024) focused on biobased, compostable plastics, evaluating their carbon footprint and environmental impacts, including microplastics. Similarly, our work emphasizes the environmental benefits of the proofing on the target substrate process, particularly its significant reduction in GHG emissions and material use compared to conventional proofing​.

The comparative analysis by Val and Lambán (2025) demonstrated the utility of LCA in identifying sustainability improvements across design and manufacturing processes. Our study aligns with this by employing ISO 14040 and 14044 standards to rigorously assess the proofing processes, highlighting the reduced energy and resource demands of the target substrate approach​.

Klein et al. (2025) conducted a detailed sustainability assessment of liquid dairy product packaging, highlighting the importance of aligning manufacturing practices with regulatory standards. Similarly, our study provides actionable insights into how proofing technologies can contribute to sustainability goals and regulatory compliance within the printing industry​.

Additionally, the work by Queiroz Cerqueira et al. (2025) on methanol production from municipal solid waste highlighted the potential of alternative technologies to improve resource efficiency and reduce environmental impact. Our research builds on this by demonstrating how alternative proofing methods can drastically reduce material consumption and waste generation in printing​.

From a technical perspective, insights from Blachowski (2021) provide foundational knowledge about printing technologies. By integrating advanced LCA methodologies, our study extends this understanding, offering quantitative evaluations of environmental impacts specific to proofing​.

Lastly, the inclusion of data from GMG Color (2025) offered a granular view of substrate impacts, bridging theoretical and practical insights. This strengthens the link between environmental assessment and actionable strategies for reducing the footprint of proofing processes​.

Additionally, here are Climate 3 Life Cycle Assessment System references which were also added to the updated manuscript:

1. Data for calculating electricity consumption; Gemis 5.1 [32]
2. Data for polyethylene film; Ecoinvent 3.8, dataset: packaging film production, low-density polyethylene [26]
3. Recycling, waste storage, and incineration of polyethylene waste in Poland [43]
4. Energy from incinerating polyethylene; BEILICKE 2020,https://dstv.deutscherstahlbau.de/fileadmin/user_upload/bauforumstahl.de/wissen/grundlagen/brandschutz/Heizwertalpha.pdf, downloaded 23.08.2022 [44]
5. CO2e emissions during PE combustion: Ecoinvent 3.8 dataset: treatment of waste polyethylene, municipal incineration [26]
6. General chemical composition of flexographic printing plate;https://iprdb.com/patent-2576-US5733948A.html, downloaded 30.4.2022 [45]
7. Solvent ink formula comes from internal, confidential data of Chespa, provided in 2022
8. Ink formula factor expressed in CO2e; Ecoinvent 3.8 [26]
9. Transport of printed raw material from the printing house to the brand owner: one delivery of the parcel source;https://timberlove.blog/e-commerce/co2-bilanz-stationaer-vs-paketversand-und-warum-das-strategisch-noch-richtig-relevant-werden-duerfte/, downloaded 23.08.2022 [46]
10. Preparation of proof on the target substrate: data provided by Chespa, which is an internal, confidential part of the research, which includes aspects such as; time and power and electricity consumption for the process of preparing proof on the target substrate.
11. Incineration of waste in the form of used proof on the target substrate: ecoinvent 3.8 dataset: treatment of waste plastic, mixture, municipal incineration RoW [26]
12. Transport packaging of cardboard flexo printing plates sent from Chespa to the printing house: ecoinvent 3.8 dataset: market for kraft paper RER [26]

These references substantiate the novelty of our work, contextualizing it within the broader literature and showcasing its contributions to advancing sustainable practices in the printing industry. We believe this addition addresses the reviewer’s concerns and strengthens the manuscript. Thank you for your valuable input.

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

The authors have adequately satisfied the reviewer's comment