MITRA Forum Question Details

Hello Richard,

Some points are a little subjective and dependant on context.

With the understanding you're planning to paint on a rigid surface pannel primed with acrylic:

1. Not painting on canvas or souple surface, the flexibility change is of little importance.

However depending whether you're mixing paints or making your own, be aware safflower oil used in Titanium whites can make them far slower drying than a genuine lead white would be. So if you're just intending to make a white ground, be careful.

2. Opacity of Lead white is closer to titanium (than zinc) so the opacity change upon ratio is fairly linear and not a huge thing. Drying-wise, lead compounds are strong driers. I would expect a bigger difference on core drying time.

3. and 4. To avoid a misunderstanding, I would differenciate strength/flexibility of film and good film formation (siccativation or crosslinking). The former is more important for 'living' surfaces as you're already clearly aware. On a metal pannel, it's less of a concern, you could paint with egg tempera and don't expect cracks.

The later film formation aspect means how much of a continuous 'thermoset' polymer the film becomes, becoming resilient to solvents and harder to damage. It's a progressive attribute of drying. If you want something to last longer, the better your drying goes the more resilient it will become.

It's more for the longevity and resiliency overall, regardless of surface. 

I hope it will help a little.

First time on the forum so apologies for the rookie mistakes I might do.

Cheers,