Radiography in transmission mode is a well-established technique to visualize the internal structure of paintings. However, for many paintings the pictorial layer cannot be clearly visualized with conventional radiography because of interference from paint on the reverse, the material composition or the regular structure of supports or surface layers. Tradictional lead white grounds in particular cause specific imaging problems not encountered with more modern white pigments such as zinc and titanium whites. A solution to this sproblem is radiography in emission mode.This study demostrates and articulates those factors that can interfere with visualization of a painting's pictorial layer using transmission radiography in visualizing such information. while emission radiography has been applied to the examination of paintings for over half century, it is a cumbersome technique that is further complicated by the need to work under dim safelight illumination when X-radiographic film is used. Therefore, the use of computed radiography using storage phosphor imaging plates for emission radiography was also investigated.