Blackout window film is the tint to apply when you don’t want any light to come in and want complete privacy. Dark rooms can use this film. Offices and stores use this film when they don’t want anyone seeing through the glass into the next room.
However, be careful if you are thinking of applying this to glass that gets direct sunlight since the solar absorbance is very high (66%) and will cause thermal stress in glass. One way to reduce thermal stress if you must use it; is apply a silver reflective 5% film first, then apply blackout on top. The silver will reflect the heat before it is absorbed by the blackout.
As a reminder tinters, always check the quality of the glass in the windows and know if there is glass breakage history at the building. Poor quality glass with nicks and chips might be hidden inside the window frame and any thermal stress at all in the window can cause issues. partially shaded windows in wintertime have more thermal stress.
Remember there are various films that can offer privacy with different effects, so ask the customer why they want film and listen to their needs so that you can offer the best solution which might be: blackout, whiteout, white matte, mirror tint like DR 5, Silver Reflective 5 or Limo (when there is not direct exposure to the sun)…don’t apply auto film to architectural glass; it’s not recommended,