In "The Light of Day," Eric Ambler creates a dysphoric Istanbul through the opposition of East and West. However, its Turkish translation "Gün Isigi" by Adnan Semih Yazicioglu tends to create a very different narrative by transforming signs related to Istanbul and some Orientalist clichés. In this study, the image of the East as constructed by the West is analyzed through Edward Said's concept of "Orientalism" (1979). The novel is divided into segments to highlight the parts taking place in Istanbul, and the clash between East and West is analyzed through the concept of isotopy and the semiotic square (Greimas & Courtés, 1982). The author's perception of the city is treated through Sündüz Öztürk Kasar's (2012) concept of "watermark translation", defining the representations of Istanbul as a translation executed in the author's mind (p. 267). To highlight the traces of the translator as covert co-author and evaluate the consequences of this interference, the meaning transformations in the target text are analyzed using the "Systematics of Designification in Translation" by Öztürk Kasar (2020a, p. 160). In connection with this, the importance of placing semiotics in the instruction of literary translation is stressed, with an emphasis on the function of the comparative analysis of the source and target texts, which may provide translation and interpretation students with an awareness that can enable them to avoid unintended meaning transformations, as well as stand behind their translation decisions of all kinds, including intended meaning transformations.