All you need to do is to find out which sensor is being used in your camera of choice, and then get the datasheet for it. The datasheet shows the spectral response curves in Red, Green and Blue. Some cameras have a problem with Red response, so it pays to remove the IR filter from the camera and replace it with a narrowband IR filter.

The peak response in each colour will be at a particular frequency. Then you go through the available LEDs and find ones that are a close match to your particular sensor. Then it is just a matter of creating an array of the LEDs and a control circuit so you can control the duration of the 'flash' of each of the colours.

This combination allows you to balance the exposure and ensure that you are emitting light that is inside the peak sensor response, otherwise you will end up missing some colour data. If you capture with a LUT that matches the density curve of the film, then that also allows you to get better details in the shadow and highlight areas of the frame. That is harder to do on a standard camera, but a machine vision camera (like the Point Grey Grasshopper series for example) allows you to apply a LUT during capture.