A "shadow tag" is a technique used in photography and visual arts to create a sense of depth and dimension. It involves placing a darker or contrasting color behind an object or subject, which helps to define its shape and make it stand out. This method can enhance the overall composition and draw the viewer's attention to the focal point of the image. In the context of digital art, shadow tags can also refer to the use of layers in software like Adobe Photoshop. Artists can create shadows on separate layers, allowing for greater flexibility in adjusting the appearance of light and shadow without affecting the main subject. This technique is essential for achieving realistic effects in visual storytelling.