RIN67630:
You still seem to not have got the catch. I am not alone with my thinking:
I thought OP was trying to predict power output from a solar panel, not measure light levels.
Sure, for light level you might need some log scale, but if you're worried about squeezing the last 0.1% power from a solar panel then you did your panel calculations wrong.
A (coloured) LED is ofcourse sensitive to a narrow spectrum (not the exact colour of the LED).
That might skew your measurement at different times of the day (e.g. morning red).
Better to use a common broader spectrum photodiode.
If you want to measure pure current (solar power), then also use a transimpedance opamp circuit.
Leo..