Gamblin PVA Size
Gamblin PVA Size
Poly Vinyl Acetate (PVA) Size
A raw canvas should be sized with Gamblin PVA Size before applying Oil Ground or oil color.
Conservation scientists recommend painters use neutral pH PVA size canvas and paper instead of rabbit skin glue. PVA Size provides a stable size layer that seals the canvas but does not swell or shrink like rabbit skin glue goes. This is because PVA size does not re-absorb atmospheric moisture.
Gamblin PVA Size is made from PVA that is free of animal byproduct, has a neutral pH, and does not yellow. It also retains its flexibility and does not emit harmful volatiles.
PVA Size on Canvas
Use any style of brush to scrub PVA Size into your canvas. You can apply PVA Size before or after stretching.
A single coat of PVA Size on the front of the canvas is usually sufficient for application. If the canvas has a very open weave showing many pinholes when held up to the light, apply PVA Size to both the front and back.
If you are stretching your canvas before applying PVA Size, ensure that canvas is stretched evenly and tightly. PVA Size will tighten a stretched canvas initially when wet but may relax somewhat once dry. PVA size will not result in any dramatic difference in the tightness of the canvas like rabbit skin glue.
For very large dimension stretched canvas or when using lightweight linen, apply PVA Size first prior to stretching. Lightweight canvas on larger stretchers can buckle and/or wrinkle on the stretcher frame when dry. Heavier weight canvas has less of a tendency to buckle or loosen.
Soap and water can be used to clean brushes after application of PVA Size.
Painting on PVA Size alone
PVA Size can be used on its own as your ground without the use of a white or colored primer over the size.
This can be used when a painter wants to allow the natural color and look of the canvas or paper to show through in parts of their oil painting. Although PVA Size is not itself a ground, it may be used in lieu of a white covering primer to protect canvas from the acidity of oil colors.
In these scenarios you should apply two applications of PVA Size to help reduce the absorbency of your canvas. PVA Size is formulated to go on very thinly without filling in the natural texture of the canvas.