MITRA Forum Question Details

For the proper, long-term adherence of oil paint, a ground must have absorbency or texture/mechanical tooth, preferably both. There is more leeway with acrylic dispersion paints as that medium is a far better adhesive on its own. Painting oil paint on a super slick, non-absorbent ground may work fine in the short-term but flaking and delamination is very possible in the future. For example, a large percentage of reverse oil paintings on glass have severe flaking issues. Now that is the extreme as far as lack of absorption and tooth but it serves to make a point.  

As far as the particular product, I cannot comment, as I have done no testing. The formulation may contain materials that provide addition tooth or the absorption may be reduced but not eliminated, etc. We do have a contact at Michael Harding Art Materials Ltd. and will send them an email to see if they would like to comment.

Michael Harding Non Absorbent Acrylic Primer.

We researched for several years to find an acrylic resin which did not suck all the oil out of the oil paint applied over it making paintings go dull. By far the most common complaint we have from newcomers to oil painting is the apparent sinking that is caused by many conventional primmers doing this. This potentially leaves the paint without enough oil acting as a glue to hold the pigment particles together possibly causing embrittlement. 

Though we describe it as non absorbent it does have minor draw but not so much as to render the paint dead looking, we also add 5% ground marble powder to add tooth and so increase adhesion between the two layers you can feel this between your fingertips if you touch a drip of it between your fingertips. It is this fine balance between the microscopic tooth and the right acrylic resin that is the secret of its successful formulation. This still results in a completely smooth surface with no need to sand.

We have done our own internal testing involving the bending of canvas to see if the primer parts company with either the support or subsequent paint layers and have found it to be every bit as strong as conventional acrylic primers.

Artists should also consider the different film strengths of various pigments within oil.

In addition they also should consider that some oil colours like the umbers particularly when mixed with turpentine or those so called odourless spirits tend to dry matte on their own, testing the mix on a sheet of glass will show this.

Sorry I cannot bring myself to describe this as a 'gesso' as I feel this is slightly misleading as a traditionalist and also advocate of the use of rabbit skin glue.

Michael Harding