Thursday, July 30, 2015

Linseed Oil and Calcite

Ruby Crowned Kinglet and Cherries  9"x12"

I have an update on my putty making project, comparing a couple different oils and also the Velazquez medium from Natural pigments.  Each putty was made by combining calcite with linseed oil.  My first introduction to putty medium was through the Velazquez medium, which is calcite mulled with a bodied linseed oil.  Bodied oils are polymerized, thickened and partially dried, with the use of heat.  Bodied oils do dry to a glossier finish than the other non-polymerized oils.  Some are oxygenated as well, others are created w/out the presence of oxygen; each have a specific personality.

I made two batches of putty to compare with the store bought Velazquez.  One batch was calcite mulled with Winsor and Newton linseed oil, a commercially processed oil.  The second batch was made with calcite and a water washed organic flax-linseed oil from Art Treehouse.  The water washed linseed begins as a cold-pressed, unrefined flax oil and is hand processed and washed of impurities in the traditional manner of the old masters. 

The difference in the putties was surprising.  

The Velazquez was thick and impasto like.  It had thixotropic tendencies, but was the least to settle out after agitation like the other oils.  It held up it's thick texture in the can and on my glass palette.

The calcite with regular Winsor and Newton linseed oil was also thick and impasto like but not as thick as the Velazquez.  It settled out a bit after agitation and I decided to add more calcite just to make sure I wasn't the cause of the thinner putty.  It was still a tad bit thinner than the Velazquez.

I believe that is the difference of using a bodied oil that was in the Velasquez medium and a thinner oil-the Winsor and Newton.  In my paint I have had similar results with the two putties, since I thin my paint with medium for glazes and layers the difference of thickness wasn't noticeable, I suppose if I wanted a thick impasto I would reach for the Rublev Velazquez with the bodied oil to hold up to thick textured passages better.

Now the most interesting discovery.  The water washed linseed oil completely melted and oozed into a puddle on my glass palette.  No matter how much calcite I added to the mixture, thinking I had made it too thin, it leveled out completely after being agitated.  I added so much calcite to the mixture that overnight it seized up in the tube I put it in and I had to discard the entire mix!  The mixture in the jar also seized up and was very difficult to mix, but after some work it returned to the original puddly consistency.  I am still trying to figure out why there was such a drastic reaction between the water washed linseed oil and calcite compared to the other oils. UPDATE  I have since learned that the Art Treehouse water washed flax/linseed oil is filtered through psyllium instead of sand, does this possibly cause it to be extra thixotropic and long compared to SRO oil?  Hand refined SRO oil is salt/water/sand refined-no psyllium--and SRO oil is much easier to work with for what I personally want in my oil painting practice. 

You can see the settled out putty with the water washed oil on the far left of the picture, (pic taken immediately after the samples had been stirred with a palette knife) and also in the left jar above.  

I have had a harder time painting with this puddly putty.  I put the concoction aside for now until I do some more research on traditional materials and hand processed oils.  I have learned so much about my materials on this journey!  I believe the old masters had much more knowledge about painting materials than we do today due to the fact that they had to process everything themselves.  Through knowing how the materials worked together to create different effects they were able to manipulate paints and mediums for their own personal expression.  While I may not continue mulling my oil paints and mediums forever, I have had a glimpse into the more intimate relationship past artists have shared with their paintings.  

I have to credit Tad Spurgeon, whose incredibly informative website and book has inspired me immensely over the past year. 

1 comment:

Debra Keirce said...

You are a chemist at heart! Glad to see you having so much fun. Thanks for sharing!