Our guest room is in the basement, and while it's perfectly cozy, and excellent for sleeping, it's not the warmest or brightest room. Here are a few ideas for adding some "sunshine" to a windowless room.
This photograph (shown above) by Melissa Kaseman (via sfgirlbybay) offers a great solution: frame a large-scale picture of an exterior scene. If you can't have a window to the outside world, then why not create one?
In this basement bedroom featured on Glitter Guide, designer Camila Pavone cleverly used window panes filled with mirrors and then framed them with curtains to mimic windows. Mirrors are a great way to add light to a space, and by giving the illusion that these mirrors are actually windows, it's easy to think the space is sunnier than it is.
Even though this room in Roger & Chris's Bold, Eclectic, & Vivacious 160-Year-Old Victorian has a window, it showcases another good tip. Don't be afraid to use bold colors and patterns. Cheery hues can liven up a space that, otherwise, might feel drab or dull. By giving visual interest to the rest of the room, you can overcome the fact that there's no window.
Or, as in this steampunk bathroom by Andre Rothblatt, you could just embrace the enclosed coziness of the room and opt for dark colors. The metallic elements here at least keep some light reflecting, but the overall mood is bold and dramatic.
This living room by Kenneth Brown on HomePortfolio shows the power of strategic lighting in a windowless room. The eye is drawn to specific places thanks to the lighted artworks, and accent lighting is placed all around the room, so that there's a generally even amount of it. There are no overly dark corners in this warm library.
Where there are plants, generally speaking, there is light. So to give the illusion of light, get yourself some plants! In a windowless room, though, you may have to go for the faux variety. But before you cringe, remember that fake plants have come a long way, and not all of them give off that plasticky, tacky vibe. Or, just embrace the fakeness, and go with a more caricatural version, like Corrie Beth Hogg (above; featured on Design*Sponge). For some more examples of fake plants that work (and some sources), check out 5 Times that Fake Plants Make the Cut.
Windows tend to break up large expanses of walls, and large-scale art can do the same, as this organized office space featured here on Apartment Therapy shows.
Add drapery behind your furniture. This bedroom from Mr. Kate shows how it can instantly give the room a focal point and drama.
Similarly, the drapery framing this bed at an IKEA showroom shows how curtains can create the illusion of windows, even when there aren't any.