Most oil paint companies produce two product lines -- student grade and professional artist quality. The difference between the two is typically the amount of pigment suspended within the oil. The oil itself will also vary as each company selects the type of oil to use. For example, Blockx (pronounced Blocks) uses linseed oil for their earths, mars and blacks, while using poppyseed oil for their other colors. Old Holland uses cold-pressed linseed oil across their entire range. However, even within the same line of the same brand, there are differences in each color recipe. The differences can be felt by picking up a tube -- the better quality oil paint will have a higher pigment load and will feel heavier due to more pigment suspended within the oil.
We encourage our artists to mix and match between the best brands and choose the appropriate colors for each particular painting. While an artist recreating an old master, such as Rembrandt, may choose a tube from Old Holland due to some of their recipes dating to 1644, another artist working on a more modern painting might prefer Blockx. While reproducing Joseph Mallord William Turner, Winsor & Newton would be best as he was a regular user of their paints. As long as the paint is of professional artist quality and is a proper selection for the task at hand, we have found the particular brand of oil paint is less important than matching the needs and preferences of the individual artist.