Usage: rgb(rAmount, gAmount, bAmount)
This filter changes the amount of color in each of the three channels.
rAmount- The amount of redness in the picture. Can range from -100 to 100 in percentage.gAmount- The amount of greenness in the picture. Can range from -100 to 100 in percentage.bAmount- The amount of blueness in the picture. Can range from -100 to 100 in percentage.
http://localhost:8888/unsafe/filters:rgb(20,-20,40)/https%3A%2F%2Fgithub.com%2Fthumbor%2Fthumbor%2Fraw%2Fmaster%2Fexample.jpg