His approach combined architectural accuracy with narrative detail. In "Bruiloftsviering in een Fries burgergezin", he recorded the social customs of a Frisian middle-class wedding with a clear style. He avoided the loose brushwork of later movements, preferring the controlled lines of the Dutch Romantic school. His cover designs often used typography and decorative borders to frame historical subjects. This method ensured that the information remained the primary focus of the work.

Modern collectors value Leich for his connection to Dutch heritage and urban history. His illustrations of Amsterdam provide a record of the city before modern expansion changed its character. The graphic quality of his book covers makes them suitable for contemporary interiors. These prints offer a balance between historical documentation and decorative art. They appeal to those who appreciate the intersection of literature and history.