Can The Healing Brush Help?
You may own a collapsible background, which is typically about 5 ft x 7 ft. They can be very convenient for a number of reasons. They fold up to about 1/3 of their expanded size, they are spring loaded so they set up much faster than almost any other form of background, and they are basically wrinkle free. These can be found B&H Photo as well as many other photo dealers.
These backgrounds are useful for head shots, 3/4 shots, and even seated poses. They are often reversible and if one side is white, they can also serve as a reflector. Sometimes however, depending on your subject, your composition may run outside the limits of this background. This can be distracting to the viewer and usually needs to be fixed in post production.
One method of fixing the problem may be to crop in a little tighter on your subject. This could work unless a body part is very close to the edge of the background. You may end up cutting off a body part that you had not intended. There are several other go to tools that you could try such as content aware fill or even content aware scale. These techniques may work depending upon your background and how it may have been lit. You could also try sampling the color, and then painting out the offending borders. You may even be willing to try the clone stamp (very tedious in many cases).
Many of these techniques may leave a blotchy appearance if the background is not lit perfectly and the material has a completely uniform appearance. This means even more time in post production! One technique that I have found to be helpful is the healing brush.
Starting on the main background, and while using a large brush cover the offending border to the background. You may find that not only has the border vanished, but the color tone is perfectly matched with the rest of the background. Hardness should be set to at least mid-level or else the edges may appear very soft. You will also want as large of a brush as you can manage while not crossing over into your subject.
This technique will certainly work with the more traditional backgrounds that are solid in color. Patterned backgrounds can be hit or miss depending upon the nature of the background. Give it a try the next time you have an annoying border to a background and you may be surprised how easy the fix may be!