## 6 Conclusions  
This study shows an LCA comparison of two proofing systems applied in a printing house in Poland. By holistically considering all processes involved in the described research, i.e., the use of raw materials, product packaging, transport, and storage, processes involved in proof printing, proof print transportation to customer, and waste disposal, we have proved that there is a 20-fold reduction in climate emissions when using the system of proofing on the target substrate developed by Chespa in comparison to the standard hard proofing system. In the case of a standard production process, it is necessary to examine all the essential processes involved in commercial printing. In contrast, in the case of using proofing technology on the target substrate, that stage can be skipped, and the focus can be on the correct preparation of the proofs in laboratory conditions. Our results confirm that the innovative process of proofing on target substrates, developed at Chespa, has a lower environmental impact than the standard proofing process. The total GHG emissions are 2610 and 132 kg of CO2e/FU for the conventional hard proof method and the Chespa method of proofing on the target substrate, respectively. At the same time, this process is characterized by lower raw material consumption compared to the conventional system. The standard proofing process requires plastic raw materials that constitute 800 kg of PE, contributing to 2.337 kg of CO2e climate emissions. In comparison, the system of proofing on the target substrate has a PE demand of 0.017 kg, and a 0.050 kg of CO2e climate emission. Furthermore, the process of proofing on a target substrate is related to lower water demand and electricity consumption (400 kg/FU) than the standard proof printing process (29,490 kg/FU). The proofing development on the target substrate reduces the waste production by 45 times compared to the standard proofing process. It should be noted that, despite the similar impact contribution for both processes, the raw material, energy usage, and water demand are much lower for the target substrate-proofing process. Finally, the target substrate proofing process exhibits less toxicity influence on terrestrial, marine, and freshwater aquatic due to requiring less raw materials, having a lower energy demand, and requiring less disposal [46]. LCA can be successfully applied and used as an assessment tool to determine the climatic impact of the proof printing process. Our results show that implementing new methods of preparing proofs and designs for printing may decrease their environmental impact, making the printing process more sustainable. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app15031136/s1](https://www.mdpi.com/article/10.3390/app15031136/s1)]([https://www.mdpi.com/article/10.3390/app15031136/s1](https://www.mdpi.com/article/10.3390/app15031136/s1)), Figure S1: Proof printing process map standard proofing and proofing on the target substrate; Table S1: Summary of climate emissions from various energy sources; Table S2: Summary of test results of each step of the investigated proof printing process; Table S3: Results of each elementary process according to impact categories studied. Conceptualization, J.N. and Z.Z.-T.; methodology, J.N. and U.B. ; software, J.N. and U.B. ; validation, J.N. and U.B. ; formal analysis, J.N., K.K. and Z.Z.-T.; investigation, J.N. ; data curation, U.B. ; writing--original draft preparation, J.N., K.K. and Z.Z.-T.; writing--review and editing, K.K. and Z.Z.-T.; visualization, Z.Z.-T.; supervision, Z.Z.-T. All authors have read and agreed to the published version of the manuscript. This research received no external funding. Not applicable. The data presented in this study are available at the request of the corresponding author due to restrictions applied to the availability of these data. Conflicts of Interest: Author [PERSON] was employed by the company Chespa sp. z. o.o.