Timber ceiling treatment

[katydid]

We have a Tassie oak timber panelled ceiling throughout our house which has been varnished. Is there any way to give a limed affect (to lighten the colour but still retain the wood look and texture)without stripping off the varnish finish?
Is it possible to add a white colourant to varnish?

[Skew ChiDAMN!!]

You could try a light lime wash, but I wouldn't recommend it. Unless skilfully done it'd look terrible.

Been there, tried that, screwed up. :o