By using a tinted lens you block some of the light with other wavelengths than the colour of the lens. So if you use a amber lens on a bluish white led, you will block a lot of light coming out that are blue or green. The led will then appear less bright.
It is better to use a led that puts out the right colours you want in the first place, so you can use all of the light and don't have to filter it. Like the warm white leds.