Which darkens wood more?

[EagerBeaver71]

Just a quick question, I know oil based polyurethane varnish darkens over time but I'd like to know which is darker when first applied, white shellac or oil based polyurethane?.

[jack620]

Urethane. White (super blonde) shellac is almost colourless. Depends on the cut of your shellac too.

[ED65]

This isn't really something that makes for a direct comparison, because typically you wouldn't apply the shellac as thickly as you would poly. Or to put it the other way you wouldn't typically apply varnish as thinly as shellac, especially today.

While oil-based finishes will generally deepen the tone of wood the most of any clear finish for just one or two coat at approximately the same dilution you might struggle to see much difference!

Best idea would be to do a quick comparison on an offcut or three, see the effects firsthand.

[ED65]

...I know oil based polyurethane varnish darkens over time...

Might be worth mentioning that while poly does 'amber' over time a lot of the darkening with lighter-coloured woods is actually the wood itself – the same colour change will occur if the wood is bare, or finished with anything that doesn't contain any UV-blockers.