[sdiy] calculating resistance to match brighness across different colours of leds?

[Julian]

Hello,

Rather than doing it 'by eye', i thought it was about time i should do this properly -

I have two leds, a red and a green.  The specs are:

Red:
Wavelength: 700
Lum. int. (mcd) @ IF (20mA): 10
IF max. (mA): 15
VF typ. (V): 2.2
VF max. (V): 2.8

Green:
Wavelength: 570
Lum. int. (mcd) @ IF (20mA): 30
IF max. (mA): 30
VF typ. (V): 2.1
VF max. (V): 2.8


If i use a 10k resistor on the red led, and i want the green one next to it to be, to the observer, the same brighness is this just 
a simple cacluation?

Im concerned that it may not be simply a case of matching the luminosity - i dont know, but does the human eye (assuming a 'normal' 
individual) have equal sensativity across the visable spectrum?

Im thinking of how the ears are more sensative to treble than bass... (?)


Julian