Golden have a recent article out where they explain that natural iron oxide pigments are running out and are going to have to switch to synthetic version in this case PBr6 instead of PBr7. I imagine this will affect other companies in time. I think I read that MH paints have either beeswax or castor wax in them as a stabiliser. I wonder if this is the issue with the Burnt Umber?
Old Holland lead white is super fast drying, so are the umbers, and so is PBr6 possibly compared to PBr7. Maybe the time is important, but that wouldn't explain why PBr6 alone without white is fine. I am a casual painter, using multiple layers over months. I've had terrible problems with beading. I also mostly use Mars Black, which is another fast-drying synthetic like the MH PBr6. A simple test for the dry time creating resistance/beading would be to let the swatches sit for a month or more and see if the the results are the same, using the remaining bits of your swatches. You could also try another synthetic i.e. Mars Black PBk11 vs. Ivory Black. My solutions have been to use a spray isolation damar varnish until they stopped making them in 2023, and now adding a bit of turp/damar to my linseed oil to soften both the surface existing paint layer and the added one. Thank you for the videos. (I also have had more problems with titanium, like another commenter here, and now use it sparingly with the lead when needed).
I am based in the UK so lead white is not part of my usual palette but I have experienced a similar beading issue across a large orange / red passage. My mix was predominantly Yellow Lake, Scarlet Lake and Burnt Umber with no additional medium. I use only Michael Harding paints as it was my understanding they have fewer (no?) adulterants and are therefore more reliably archival. I hope we aren't uncovering a problem with their qualities. Thank you for your methodical investigation of this issue, I will follow along with interest.
Regarding the RGH cremnitz white, there is an aluminum stearate additive. Artist Luis Borrero’s youtube channel has a video where he visits the RGH facility and films a batch of cremnitz white being made. One experiment I’m interested in seeing is whether or not oiling out with something like rublev’s oleogel would get different results.
I've had beading up happen while using a high percentage of titanium white mixed with various paint colours. White is very "fat". Lots of oil. It really creates a seal on the canvas or panel, and doesn't leave much in the way of "tooth" left for further layers of paint to adhere to.
Golden have a recent article out where they explain that natural iron oxide pigments are running out and are going to have to switch to synthetic version in this case PBr6 instead of PBr7. I imagine this will affect other companies in time. I think I read that MH paints have either beeswax or castor wax in them as a stabiliser. I wonder if this is the issue with the Burnt Umber?
Old Holland lead white is super fast drying, so are the umbers, and so is PBr6 possibly compared to PBr7. Maybe the time is important, but that wouldn't explain why PBr6 alone without white is fine. I am a casual painter, using multiple layers over months. I've had terrible problems with beading. I also mostly use Mars Black, which is another fast-drying synthetic like the MH PBr6. A simple test for the dry time creating resistance/beading would be to let the swatches sit for a month or more and see if the the results are the same, using the remaining bits of your swatches. You could also try another synthetic i.e. Mars Black PBk11 vs. Ivory Black. My solutions have been to use a spray isolation damar varnish until they stopped making them in 2023, and now adding a bit of turp/damar to my linseed oil to soften both the surface existing paint layer and the added one. Thank you for the videos. (I also have had more problems with titanium, like another commenter here, and now use it sparingly with the lead when needed).
I am based in the UK so lead white is not part of my usual palette but I have experienced a similar beading issue across a large orange / red passage. My mix was predominantly Yellow Lake, Scarlet Lake and Burnt Umber with no additional medium.
I use only Michael Harding paints as it was my understanding they have fewer (no?) adulterants and are therefore more reliably archival. I hope we aren't uncovering a problem with their qualities.
Thank you for your methodical investigation of this issue, I will follow along with interest.
Regarding the RGH cremnitz white, there is an aluminum stearate additive. Artist Luis Borrero’s youtube channel has a video where he visits the RGH facility and films a batch of cremnitz white being made.
One experiment I’m interested in seeing is whether or not oiling out with something like rublev’s oleogel would get different results.
I've had beading up happen while using a high percentage of titanium white mixed with various paint colours. White is very "fat". Lots of oil. It really creates a seal on the canvas or panel, and doesn't leave much in the way of "tooth" left for further layers of paint to adhere to.