Can decals or letters be applied on the "inside" of glass?
Yes, decals and letters can be ordered for an "inside glass" application.
When it comes to window decals, window lettering and window graphics (a combination of window lettering and printed window decals) there are two ways to apply the adhesive vinyl to the window. The typical form of application is "outside window" which is the industry standard. The other vinyl application method is "inside window". Here is a brief explanation of both...
OUTSIDE GLASS WINDOW APPLICATION:
Most all sign companies produce their window graphics, window decals and window lettering to be applied to the "outside" of a glass surface. This means that the cut vinyl lettering or digitally printed graphics have adhesive on the backside of the material. Outside applications are typically easier to install and run into less visual or installation issues in comparison to an "inside of glass" installation. Vinyl lettering and vinyl decals that are applied via the "outside glass" method will withstand the elements and can be cleaned with soap and water or a mild cleanser.
INSIDE GLASS WINDOW APPLICATION:
Vinyl decals, graphics and lettering that need to be applied with an "inside glass" application are technically printed in reverse (or mirrored) so that the adhesive side of the vinyl material is on the "front" of the decal. This makes it possible to adhere the vinyl to a window from the "inside the glass" facing outwards. Lots of people inquire about this type of application method, and tend to think that it would look better than "outside glass" window graphics, but in all actuality inside glass applications can be a bit more tricky to install and incur installation and visual problems that aren't an issue with outside glass vinyl.
Some of the issues that inside glass vinyl can experience, whether they are installed by a professional or a novice, include noticeable air bubbles in between the vinyl and the glass; impaired visibility because of window tint and muted decal or lettering colors because of window tint.
Ultimately, we always encourage an outside glass application method for our vinyl products, for ease of installation and for the simple fact that the product will last just as long as inside glass vinyl. The only real reason to order decals or lettering for inside glass applications is in the case where building codes dictate the necessity or if your particular area experiences a high amount of vandalism.