What is the fine-grained topic of the following text: Dyce's strong colours, firm outlines, naturalistic detail, and thoughtful sincerity of approach formed a bridge between the Nazarenes and the Pre-Raphaelites, and Ruskin said that it was Dyce who gave him his ‘real introduction’ to the Pre-Raphaelites when, at the 1850 Royal Academy exhibition, he ‘dragged me literally up to the Millais picture of the Carpenter's Shop, which I had passed disdainfully, and forced me to look for its merits’. Only return the topic.
Dyce's influence on the Pre-Raphaelites and Ruskin's appreciation of Pre-Raphaelite art.