「合作畫」的創作形成，可分為：即席合作、非即席合作、與計畫型合作等不同創作方式。「南張北溥」即席合作畫，乃指張大千（1899-1983）與溥心畬（18961963）兩位近代水墨大師，在長期交往中，每於會面時，即席輪流對畫互題，所合作形成的畫作。《寶島長春圖》卷，為國立歷史博物館（以下簡稱史博館）典藏文物，此巨幅長卷，屬於計畫型合作畫。係史博館策畫，邀請張大千、黃君璧（1898-1991）等十位水墨畫家，合力共同創作形成。 同樣是合作畫，在不同的創作動機下，形成不同的宗旨目的。成員組合的差異，題材的不同，影響藝術效果的呈現。畫幅規格大小影響創作空間的需求，以及創作速度，創作過程，面臨挑戰，產生的藝術效果等層面，這些都是形成合作畫這一特殊創作形式的關聯性議題。本文擬就這些議題，於上述兩者之間創作形成的異同做一探究，並概略敘其大要。

The painting processes for collaborative paintings can be classified into impromptu, non-impromptu, and project-based collaborations.“Zhang in the South and Pu in the North＂impromptu collaborative paintings are a distinctive type of painting collaboratively completed by the leading contemporary Chinese painting masters, Zhang Daqian（1899-1983）and Pu Xinyu（1896-1963）. Zhang and Pu impromptu painted and wrote on the work alternately to complete the impromptu collaborative paintings whenever they met each other. The large picture scroll,“Evergreen Spring in Taiwan,＂ is a project-based collaborative painting commissioned by the National Museum of History, which invited 10 artists including Zhang Daqian and Huang Junbi（1898-1991） to collaborate on the scroll. Diverse motivations, purposes, artists, and topics create various artistic effects. Frame sizes influence the space requirements for painting, painting speed, painting processes, challenges confronted, and artistic effects. These are relevant issues for the unique painting style of collaborative paintings. This study attempts to explore the similarities and differences between“Zhang in the South and Pu in the North＂impromptu collaborative paintings and the“Evergreen Spring in Taiwan＂ commissioned by National Museum of History, presenting a compendium how these paintings were composed.