Presentation Information
[O12-P95]Physical Effects of Ink-Grinding Force on Soot Particle Size and Color Evaluation of Calligraphic Works
*Keigo Yamawaki1 (1. Fukui Prefectural Wakasa Senior High School)
Keywords:
Ink-grinding force,Soot particle size,Sensory evaluation
Background and Purpose
Japan possesses numerous historical cultural properties related to calligraphy. As calligraphy is currently being considered for registration as a UNESCO Intangible Cultural Heritage, it has become an important target of national-level preservation efforts. Despite this, evaluations of calligraphic works—particularly ink color and texture—have largely depended on expert intuition and experience. Quantitative physical data explaining why a work appears a certain color or texture remain insufficient.
This study focuses on the physical process of ink preparation, specifically the force applied during ink grinding. The objective is to clarify how grinding force influences soot particle size and distribution, and how these physical properties relate to color impressions and the evaluation of calligraphic works. Through this approach, we aim to establish a physical basis for ink color evaluation in calligraphy.
Methods and Results
Three experimental approaches were conducted.
Method 1 examined the relationship between grinding force and soot particle size. Ink was ground under two force conditions, 3 N and 20 N, with the force controlled using a balance scale. The ink solutions were diluted to 1/1000 and observed using an electron microscope. Ink ground at 3 N exhibited relatively small and uniform soot particles, whereas ink ground at 20 N showed a wide particle size distribution with agglomerated structures. These results indicate that stronger grinding force produces larger and more heterogeneous soot particles, while weaker force yields finer and more uniform particles.
Method 2 investigated soot particle distribution on paper after writing. Ink was prepared under three force conditions (20 N, 40 N, and 70 N), and characters were written on traditional Japanese paper using a brush. The samples were observed using a scanning electron microscope. However, clear identification of soot particles and discrimination from paper fibers were difficult. This is likely due to soot particles penetrating deep into the paper structure, as well as selective deposition of finer particles through the brush, placing them beyond the observable resolution.
Method 3 evaluated the relationship between grinding force and perceived ink color through sensory evaluation. Ink was prepared under five force conditions: 1, 5, 10, 20, and 40 N. Fifteen calligraphic works were produced using three script styles (kaisho, hiragana, and gyosho). Sensory evaluation was conducted with 32 participants, who rated each work on a scale from 1 to 10. For all script styles, average scores increased with grinding force. When ink color was visually unified and participants were asked to select the best work, the most frequently chosen force conditions did not always coincide with the highest numerical ratings.
Discussion
The sensory evaluation results suggest that ink color significantly influences the impression of calligraphic works, but does not necessarily align with evaluations of technical skill or character form. This implies that color functions as an independent factor in calligraphy evaluation, distinct from technical or morphological assessments.
Future Work
Future studies will increase the number of participants to improve statistical reliability and will compare ink colors of historical calligraphic cultural properties. The ultimate goal is to identify grinding force conditions capable of reproducing specific ink tones for objective evaluation and preservation.
Acknowledgements
The authors thank Professor Kazumasa Yamada of Fukui Prefectural University for providing access to electron microscopy facilities, and Mr. Ipitsu Kishimoto of the Jakuetsu Calligraphy Association for assistance with sensory evaluation.
References
Azscience Co., Ltd. (2023). What is a scanning electron microscope (SEM)? Principles and characteristics.
Wada, A., & Aoi, T. (2008). A study on ink color in ink-written characters: Analysis using image processing software I.
Yamaguchi, S. What is sensory evaluation and its proper role.
Japan possesses numerous historical cultural properties related to calligraphy. As calligraphy is currently being considered for registration as a UNESCO Intangible Cultural Heritage, it has become an important target of national-level preservation efforts. Despite this, evaluations of calligraphic works—particularly ink color and texture—have largely depended on expert intuition and experience. Quantitative physical data explaining why a work appears a certain color or texture remain insufficient.
This study focuses on the physical process of ink preparation, specifically the force applied during ink grinding. The objective is to clarify how grinding force influences soot particle size and distribution, and how these physical properties relate to color impressions and the evaluation of calligraphic works. Through this approach, we aim to establish a physical basis for ink color evaluation in calligraphy.
Methods and Results
Three experimental approaches were conducted.
Method 1 examined the relationship between grinding force and soot particle size. Ink was ground under two force conditions, 3 N and 20 N, with the force controlled using a balance scale. The ink solutions were diluted to 1/1000 and observed using an electron microscope. Ink ground at 3 N exhibited relatively small and uniform soot particles, whereas ink ground at 20 N showed a wide particle size distribution with agglomerated structures. These results indicate that stronger grinding force produces larger and more heterogeneous soot particles, while weaker force yields finer and more uniform particles.
Method 2 investigated soot particle distribution on paper after writing. Ink was prepared under three force conditions (20 N, 40 N, and 70 N), and characters were written on traditional Japanese paper using a brush. The samples were observed using a scanning electron microscope. However, clear identification of soot particles and discrimination from paper fibers were difficult. This is likely due to soot particles penetrating deep into the paper structure, as well as selective deposition of finer particles through the brush, placing them beyond the observable resolution.
Method 3 evaluated the relationship between grinding force and perceived ink color through sensory evaluation. Ink was prepared under five force conditions: 1, 5, 10, 20, and 40 N. Fifteen calligraphic works were produced using three script styles (kaisho, hiragana, and gyosho). Sensory evaluation was conducted with 32 participants, who rated each work on a scale from 1 to 10. For all script styles, average scores increased with grinding force. When ink color was visually unified and participants were asked to select the best work, the most frequently chosen force conditions did not always coincide with the highest numerical ratings.
Discussion
The sensory evaluation results suggest that ink color significantly influences the impression of calligraphic works, but does not necessarily align with evaluations of technical skill or character form. This implies that color functions as an independent factor in calligraphy evaluation, distinct from technical or morphological assessments.
Future Work
Future studies will increase the number of participants to improve statistical reliability and will compare ink colors of historical calligraphic cultural properties. The ultimate goal is to identify grinding force conditions capable of reproducing specific ink tones for objective evaluation and preservation.
Acknowledgements
The authors thank Professor Kazumasa Yamada of Fukui Prefectural University for providing access to electron microscopy facilities, and Mr. Ipitsu Kishimoto of the Jakuetsu Calligraphy Association for assistance with sensory evaluation.
References
Azscience Co., Ltd. (2023). What is a scanning electron microscope (SEM)? Principles and characteristics.
Wada, A., & Aoi, T. (2008). A study on ink color in ink-written characters: Analysis using image processing software I.
Yamaguchi, S. What is sensory evaluation and its proper role.