Room darkening shades
Room darkening shades are commonly used in bedrooms as well as home theatre or multimedia room where you want to completely block the sunlight from penetrating into the room. This is absolutely useful if you have young children or even adults who take naps during the day or if you do not want to be disturbed by the harsh sunlight in the morning.
The only type of room darkening shades that can effectively shut out light from the room is the honeycomb shade. What are honeycomb shades? They are the accordion looking shades that are made out of sturdy fabric material. If you turn the shades to the side it actually looks like a stacking bee hive which is the reason why it is called the honeycomb.
These type of shades are excellent not just to keep the light our but they are efficient in keeping the temperature down as well. Due to bee hive design of the shades they are able to protect the room from the outside heat better than the conventional blinds. Some comes in double layer so they are able to insulate the heat more effectively.
The better room darkening shades use the same material as the normal honeycomb blinds but they usually have a metal layer in the middle which is used for blocking the light completely from the outside. The shades usually are wide on the street side so from the outside nobody can tell the difference but on the inside there is a variety of colors to choose from. In order to completely block out the light I would recommend going for inside mount shades only. You can still use outside mount ones but it is more complicated to ensure completely block penetration of light into the room.
Even for inside mount shades you would still need to attach blackout sidetracks on the side of the window. The function of the sidetracks is to ensure that when the shades are closed there is no light coming through at the side of the window frame. The side tracks can be cut into the length that you want and easily installed either using magnets or strong double sided tape.