I'm always right. Apart from this time it seems I read somewhere its all to do with rods and cones and the wavelengths of colours but can't find it now so I must be wrong ..
misses tells me all the time its ok to be rong all the time
if theres a way of getting a brighter led lamp so the red filler works well and runs off a lithum batry in the handl like the 150 would that be any good to you i would think you could leve the filter on if it was a good size led.id think this would do the job for me on some realy shy stuff