1. GRAPHIC UPDATING — Lightboxes are usually designed for frequent replacement of the graphic (such as a monthly or seasonal promotional message), so they provide a quick method for opening and accessing the graphic without tools. Conversely, (non-lightbox) electric signs are usually designed for long-term or permanent display of a graphic (such as the name of a store), so they don’t need such easy access to the graphic.
2. MATERIAL — Lightboxes are usually built of extruded aluminum, whereas electric signs are often constructed of steel, wood or plastic. Aluminum is generally considered to be more ‘upscale’ in both rigidity and elegance, but other materials are often more economical.
The economy of steel, for example, is especially relevant because electric signs are often much larger than lightboxes, for building-mounted and highway signage that’s intended for viewing from greater distances. One might think rigidity should be more important at larger sizes, but (a) there are other more economical ways to strengthen jumbo signs besides switching base materials; and (b) rigidity is more critical for lightbox frames due to the unique, moving mechanisms they contain (see #3 below).
3. GRAPHIC SECURITY — Lightboxes usually sandwich the backlit film loosely (without glue) between two lenses so that it can be removed without wasting a lens, when the image needs to be updated. This is achieved via some combination of flip edges, slide frames, snap frames and/or hinged doors. Electric signs usually contain only one translucent lens layer, for the sake of simplicity, longevity, and also to decrease the need to manage moisture condensation. Most electric signs do not use a backlit film for their artwork, but they can — and if they do — the printed film must be glued to the lens, which renders the lens also wasted whenever the image needs to be replaced.
