Not all rooms have large bay windows, in fact some rooms have no windows at all. If there's no natural light, and minimal electrical lighting, spaces appear dark, flat and very unappealing. No light is bad but shooting a large common space with a poorly lit kitchen at the far end and windows behind me illuminating only the foreground is much worse. Here's an example:
I did what I could to add light using multiple flash exposures blended with the poor ambient. As you can see there's still uneven lighting, little contrast and varying yellow/blue hues between the light and dark areas. I still don't have a solution to this particular lightmare, but I've devised a system to handle rooms that look like this:
I have pretty good coverage from the ceiling lights but no windows. This image was the first ambient exposure. My problem with this photo besides the ovcious yellow tint and bright light is there's no definition in the areas between walls. I used "Flambience" for all my interior photos, a technique that's becoming increasingly popular and replacing HDR bracketing. I won't get into the details here but the gist is a flash exposure and an ambient exposure are overlaid, each using the other to fix shadows and the flash layer being used for it's more consistent, correct color.
Here's The first flash photo, one flash filling the whole room. If this were a room with a window this would be enough.
It's too bright in the front and too dark in the back, not to mention the doorway leads into a dark abyss. There's also an ugly shadow behind the light, but it's a start. I now switch from the large flashhead I used for this shot and use my handheld speedlight, standing in each corner and using a flexfill to bounce white light. Without the flexfill the flash will pick up color from the walls. That wouldn't be such a big deal in this gray room but in a yellowish room it's very important.
Now you can see on each wall opposite where I'm standing there's much more contrast between the far wall and the side wall (more pronounced in the right photo). In post I stack my photos with the first flash picture on the bottom (let's call that A), followed by these two flash photos (B will be me on the left, C me on the right), a flash photo to light the doorway (not going to include that here) and finally the ambient exposure on top (D), hidden for now and with the blend mode set to luminosity. I start by giving B and C a mask, hiding them completely.
Now I Take the gradient tool and select the mask portion of Layer C, dragging it From midway in the room to the left. The result will be exposing the half of the room without me in it. Now I do the same for Layer B, selecting the mask and this time dragging the gradient tool to the right. The result looks like this:
Now you can see the picture has much more dynamic range in the far corners than photo A. I lighten the doorway layer on and then merge all of the exposed layers (Shift+Command+E). I correct the color using the curves tool, which I won't get into here, then I reveal layer D, setting the opacity to roughly 60% (and set to luminosity blend mode). I then give layer D a see-through mask and use a brush set to about 25% opacity and paint out a good deal of it around the corners and by the shadow the light fixture is creating.
The one shadow still prominent is that behind the light. I use quick selection to grab the light, inverse the selection (Shift+Command+I) and then choose the brush tool. I hold option and click on a gray color just outside the shadow, set my brushes opacity to 25% if it isn't already, and paint gray into the shadow to blend it in with the surrounding ceiling.
Finally I correct the perspective using transform, add a filter I've made in raw editor and this is the final product:
It's a little more time consuming to shoot and incorporate those two extra photos, but I think the result justifies the effort.