How to invert the colors in an image

Hi, I want to invert the colors in a grayscale image that i am reading with matlab. Whenever the image is black, matlab gives me 0 values, and whenever the image is white matlab gives me certain values. I want to invert this so whenever is black matlab gives me the values and whenever is white matlab gives me 0 values. Can you help me with this? Thank you!

Answer 1

[Dishant Arora]

 doc imcomplement

[Sebastian]

Thank you!

Answer 2

[Gerard Broussard]

You can also do something like

colormap(flipud(gray))

if you don't want ot re-compute the image you're working with