Historically wood panels were preferred for easel pictures until the 17th century. Often made of seasoned oak for durability, 2 or 3 wide planks would be joined together with a supporting ‘cradle’ on the back. They were prepared with a chalk based ground called Gesso. Weight limited their use to smaller sizes. Canvas was generally lighter and replaced panels as affordable canvases became available early in the industrial revolution. Today light weight panels allow artists to revisit the advantages of panel painting, but in larger sizes. They are able to withstand very vigorous painting techniques, they allow the build up of very heavy paint thicknesses without sagging problems, and they allow significant textural effects or the attachment of extraneous weighty materials easily. Of the various types Masonite should be avoided as too heavy and problematic. MDF can regarded as merely a type of heavy duty cardboard in that it shares many characteristics, and so long as protected from moisture may well be the best choice currently. 2.5mm (2 point 5) MDF with a supporting cradle of 18 x 8 mm (approx) wood is capable of being very similar in light weight as canvas in large sizes.