The voltage drop of a Led depends a lot on the colour it emits. Some diodes may have a 0.7 voltage drop, but leds usually have a much higher voltage drop. For infra-red leds it's about 1.8 volts, UV can be close to 4volt.
There's little harm in using a resistor with a higher value as needed, but a red diode (~2v) will shine much brighter as a blue one (~3.2v) when you use the same value resistor.