Colorimetry

[bio90]

I am interested to find out about filters when carrying out colorimetry. From what I can look up, it says that filters are used to 'select the appropriate wavelength of light'.

 

I would like to know:

1. How do you choose the right filter?

2. How does the filter select the appropriate wavelength of light?

3. Why is this particular wavelength most appropriate?

 

Any help would be so much appreciated thank you.