Hello Again Marvin:
What we agree on:
I definitely agree with you that the medium does not make the painter. I have said that a skilled painter could take peanut butter and honey and make a medium that would sing and be a tasty treat too! For my process right now, my medium works for me.
I also definitely agree with you that one does need to be careful of the materials one uses. Just because I don't find turpentine harmful to me, does not mean that it won't harm anyone - people with chemical sensitivity or breathing problems might well be adversely affected by it.
Where I diverge:
However, I don't believe that it is reason enough to warn everyone away from using these materials.
Just as we have to experiment with our materials, so we have to make decisions based on that experience - but truth to one is not necessarily truth to all.
There are those whose truth says that mineral spirits as a thinner does not work with oil paints the same way that turpentine does - it creates a weaker paint film via its evaporation. That alkyd mediums can flake and delaminate and that they may not stand the test of time. That hand mulling your own paints is the only way to go. Linseed oil should be used and it should not. Black Oil is great and horrible. Lead paint is wonderful and deadly.
The amount of individual truths out there is dizzying.
I think we all need to make these choices for ourselves. That does not mean that your warning about these products is unwarranted, especially if it causes someone to test things for themselves and make their own informed decisions. But oil painting is 600 years old and it has been done for the last 550 years with traditional materials - I believe that artists should research and think for themselves before abandoning them.
That said, I use alkyd medium in my undertones. I have Gamblin's Permanant Alizarin, and I paint on acrylic gesso boards. I rejected Gamblin's Flake White Replacement and Gamsol. I do these things because I have researched them and believe that the benefits they provide work well into my process.
But thanks for the warning.
