MITRA Forum Question Details

These are questions subject to a degree of personal relativity of what's considered most worth while. As I type this I recall some released study on paint films done by I believe the Smithsonian. Titanium white bound solely in alkyd performed quite well and better than titanium in linseed. Linseed Lead white performed very well in the general goldielock zone, but alkyd lead white (like zinc white) aged to a too hard slighly brittle state.

Now perhaps alkyd mediums added to titanium oil tints on a panel are all that's needed, but how much alkyd? Would alkyd titanium white be better? Regarding lead white, is ASTM II really that bad considering that ASTM II ​pigments show their most noticeable fading in tints where they drop well below ASTM II to III or even IV?​​

Unfortunately when it comes to being exact I'm afraid here that I simply don't know.

Fellow painter, Marc.

​Thank you, Marc.

1. When you say "alkyd lead white" do you mean lead carbonate mulled into an alkyd paint or lead carbonate paint with some alkyd used as a medium by the painter?   The former brings much more alkyd to the paint layer than the latter .  

2. "Titanium white bound soley in alkyd"...  an alkyd paint or an oil paint with some alkyd used as a medium by the painter?

I've never used alkyd paints, if that is what you are referring to, but have been using some alkyd only as a medium in my oil paints as the least yellowing, hardest and most flexible medium (recommended by one of the paint experts on AMIEN a decade of more ago.)

​One of my traits, perhaps a fault, is too segue needlessly.  The alkyd lead white was a basic lead carbonate mulled in​ alkyd and made by Winsor & Newton not lead white oil paint with alkyd medium added. Winsor and Newton no longer make it so why did I bring it up?

Again a pigment mulled in alkyd. This was also probably made by Winsor & Newton. Supposedly it's safe to mix the two types of paint but how much testing have they actually done on it? Probably safer to just keep mixing alkyd medium into oil paint.

In my own practice I've found that stand oil is the most flexible, but then I've only tested paint and oil films that are a few years old.​

Marc.​​

​Mentioning the brittleness of titanium alkyd paint is worthwhile as it suggests that there is a limit to how much alkyd can be added to titanium pigment to create a paint before it becomes a problem.  My use of alkyd falls far short of this and is used by me on advice by a paint/organic chemist from the U of NY Rochester a few years ago on Amien, and I just wanted you to clarify your statement,  Thank you.

According to her, as I recall, alkyd medium passes the flexibility test  better than any other oil based medium (a sheet coated with titanium is run around a rod of a progressively smaller diameter to see how much bend the paint layer can withstand before failing.)

I'm hoping to hear further from someone with a materials background who can add another point of view to the results discussed in the Sept 2023 issue of "Just Paint."  I contacted Golden (WB oil colors) and received this helpful reply from Cathy Jennings, materials specialist:

 Thank you for your questions.  We will take them individually below:

1. Would an alkyd medium impart enough strength, hardness and flexibility to titanium white to replace that of lead white?
1. We believe that using an alkyd medium with Titanium White oil paint is likely to increase the strength, hardness, and flexibility of the Titanium White paint film.   How much the medium does so will depend in part on the amount of alkyd being used, the thickness of application, and the individual characteristics of that particular medium.  We have not done this type of comparison test with alkyd mediums.      
2. Could lead white be used in bottom paint layers of a landscape if covered with subsequent layers using titanium white? Would the titanium be opaque enough to protect the lead white and pigments below? 
1. It might well be beneficial to use Lead White underneath Titanium White.  However, we have not done lightfast testing of lead white mixes underneath Titanium White layers.  If the lead white blend is one without great lightfastness, and the Titanium White is applied in a thin enough layer that the lead underpainting is at all influencing what is seen, then it is likely that the underlayer will still fade with exposure over time. ​
   

The titanium alkyd white (no zinc included) wasn't too brittle the alkyd lead white was. My mild concern was compatability of a paint completely bound in another vehicle other than a standard drying oil. Not that I'm aware of this being a problem with alkyd paints.

Thank you for relaying the responses from Golden.

I myself, apart from mixing a little lead white with my titanium white, give no further thought to permanence once I start painting. Choices are made before I start. Then I put them out of my head. Making the image becomes all that counts.

Marc.​​​