Re: When I looked through a red balloon filled with helium it neutralized......

Ask yourself: why does anything look colored when you look through it?
Firstly, you know it must be letting some light through if you can
see through it at all (ie. it's tranparent or translucent).
But, secondly, you can say that, if white-light going in is coming
out colored, then some colors of light are not getting through.

So, to take your example, the red balloon is letting red light through,
but must be either blocking or cutting down any blue or green light etc.
What I would expect you to see then, is that non-red objects would
appear much darker than normal, whilst reddish objects would be
unaffected, and indeed, by contrast, may appear brighter or even whiter
to the eye.

What is doing the blocking of the non-red colors?  It's the pigment
in the balloon.  The Helium is essentially colorless and should have
negligable effect.  (Of course, in science, the real proof is in 
experiment, and you could try filling another red balloon with air
to see for yourself whether I am right or wrong!)

Interestingly, Helium does have a more dramatic effect on sound,
due to its lower density than air, so Helium filled balloons can be
used as kind of "lenses" to focus [or spread] sound.