When he saw a streak or smudge that seemed unnatural, he had to contact NPM experts to find out whether the suspicious element was actually present in the original painting, and if not he then Photoshopped it out of the image.
諶懷椿表示，每當看到不自然的線條或黑點，便須請教故宮專家，確定是否為原畫所有，如果是髒點，就用 Photoshop 繪圖軟體修掉。