Prior to the 19th century, to “illustrate” meant to illuminate or shed light upon (“illustrate”). It was further defined as meaning to make something clear by way of examples or instances (“illustrate”). However, with the increasing importance of graphic images in periodicals of the 19th century, the term came to be synonymous with visual depiction. Illustrations were, at first, seen to be inferior to the written text and functioned only as accompaniment to articles, poems, fiction and the like. Toward the latter half of the century, a proliferation of periodicals which defined themselves in terms of their illustrated nature increased as a byproduct of the adoption of more mechanized reproduction techniques (Beegan 8). One primary example is The Yellow Book, which staked a firm claim to give equal due to both “letterpress” and “pictures,” equalizing the two and allocating merit to the art of illustration. With the advent of photomechanical reproductive processes, 1890s photographic illustrations became a source of information in and of themselves, supposedly getting the reader closer to the object of the image. By this time, illustrations appeared in almost every magazine and came to be expected when opening up the pages of a periodical.
For more information, see “Illustration” in the Dictionary of Nineteenth Century Journalism, on C19.
Beegan, Gerry. Introduction, The Mass Image: A Social History of Photomechanical Redporuction in Victorian London. (Houndmills: Palgrave Macmillan, 2008): 1-28. Print.
“Illustrate,” OED Online. Oxford University Press, 1899. 22 October 2015.