Prussian blue pigment: Bridging the historical palette to modern innovations
Authors: Singh Manager Rajdeo , Sharma Anjali 
Published: June 2024

This comprehensive review explores the multifaceted realm of Prussian Blue, a pigment with a rich history and varied applications tracing its origins, artistic applications, and chemical properties. Beginning with its origins as a laboratory creation, the paper traces its evolution into a revered pigment in the artistic world. The review explores the electronic transitions responsible for Prussian Blue's deep blue hue, shedding light on the intricate chemistry behind its vivid coloration. Additionally, the pivotal role of iron ions in determining the pigment's properties is examined in detail, highlighting the importance of precise composition in achieving desired color characteristics. Challenges in the reintegration of Prussian Blue into conservation and restoration projects are also explored, emphasizing the importance of careful preservation techniques to maintain the pigment's integrity and vibrancy. The review discusses the pigment's lightfastness and stability, addressing common issues such as fading and discoloration over time. A notable phenomenon of bronzing particularly associated with Chinese Blue has been characterized by the appearance of yellow or brown hues on the surface of the pigment, that has puzzled artists and conservators for centuries. The review delves into the underlying causes of bronzing, examining factors such as environmental conditions, pigment composition, and application techniques. The review explores the pigment's interactions with other blues and whites, offering insights into the spectrum of shades achievable through careful color mixing and layering techniques. The paper revisits the perennial debate surrounding the permanence of Prussian Blue. While some argue for its enduring stability and longevity, others point to instances of fading and discoloration observed in historical artworks. The manuscript navigates these conflicting perspectives, providing an understanding of Prussian Blue's permanence in different contexts. Prussian Blue stands as a testament to the symbiotic relationship between science and art, where its molecular structure and vibrant shades continue to inspire both chemists in laboratories and artists in studios. The Prussian Blue emerges as a captivating convergence of art and chemistry that has left an indelible mark on laboratory benches and artists' canvases. The unique interplay of ferric and ferrous ions, not only renders a deep blue color but also makes it sensitive to the variation of its environment. The interplay of its refractive index, bronzing tendencies, and tinting strength shapes its artistic applications, influencing the vibrant hues it contributes to diverse palettes. The permanence paradox surrounding Prussian Blue underscores the importance of precision in its preparation. As artists mix and blend, the pigment unveils its versatility, playing a pivotal role in color harmonies and shade variations. Beyond its role in art, Prussian Blue finds diverse applications in medicinal and industrial contexts. From its use as an antidote for heavy metal poisoning to its incorporation into high-performance materials such as batteries and sensors, Prussian Blue continues to demonstrate its versatility and utility in modern society. The review highlights these varied applications, showcasing Prussian Blue's enduring relevance and evolution beyond its historical roots.