Created Unassigned: Issue with colorizing image using RGB values [1402]

I have an image I'd like to colorize using RGB values (and eventually, HSL), but for whatever reason I'm only able to pass in a hex value as a parameter for my image to be successfully colorized.

Is there anything inherently different between:

image.Colorize(new MagickColor(255, 255, 0), (Percentage)50); -DOES NOT WORK
image.Colorize(new MagickColor("#ffff00"), (Percentage)50); -WORKS

Assistance with this would be greatly appreciated, thanks.

Ben