The Illuminated Sketchbook of Stephan Scriber anno 1494. This is a surprisingly well-preserved sketchbook by Stephan Scriber, a monk from South-West Germany. This book is considered a playground for ideas for his work as an illustrator. This gives an exciting insight into how ideas and layouts for illuminated manuscripts were tried out and skills developed in producing late-gothic bibles.
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The Illuminated Sketchbook of Stephan Scriber