I shot my image in RAW and used the grey scale converter and sliders within the raw converter to achieve the following results from the following colour image, followed by the natural Grey conversion.
First up is a simulation of a Red Filter, here a Red filter will filter or allow mainly red light to pass hence the 'red' in this image is a lot brighter and all the other colours are less intense.
Second is the simulation of the Yellow filter, interestingly the Green block also appears more intense because Green is made up from Yellow and Blue, the Blue and Red blocks appear very dark.
Next up was the Green filter, the green block here appears to be no lighter than the previous conversion, probably because I also lowered the level of yellow as can be seen when comparing the last two images.
Finally the blue filter was applied showing an intense blue block with all other blocks looking dark.
I have played with colours previously in this manner when converting to Black & White, but this time around I can now see the effects on all colours and after reading the course notes have a better understand of colour and why!