The answer to this question is “yes, and no.” Black tends to be easier to remove because black absorbs nearly all wavelengths of light making laser treatment very effective. Colorful tattoos tend to be more difficult because it is necessary to use the correct wavelength to effectively shatter the colorful ink particles. At the same time, however, black ink tends to be applied more densely than other colors. Ink density plays a major role in how easily a tattoo can be removed. The more dense and dark the ink is the more sessions will be required to shatter all of the ink so that the immune system can flush it out.
Below are some examples of colorful and black only tattoos throughout the laser tattoo removal process. As you can see both colors and black fade well with the Trinity Laser by Astanza used at Vanish.