How Liquin applies to the Fat over Lean Principle

Any discussion about oil painting and medium would be incomplete without mentioning the FAt over Lean rule... 

The premise of Fat over Lean is that each successive layer needs to be fatter (usually meaning more oil content thus slower drying) than previous layers, so that the top layer does not dry faster than the previous layers.

Contradicting this rule, that is, by applying leaner (less oil content) paint over fattier layers, will result in the top layer cracking (after it's dry and gone hard) over the still drying pliable lower layers or even flexible canvas. Thats why it's more sound practice to paint on canvas boards or any support that limits this flexibility and thus is more archival.

According to Winsor & Newtons Q&A, the real objective of the fat over lean principle is to apply ever more flexible layers above less flexible layers. By adding more Liquin one also makes the paint more pliable, thus each successive layer would become more flexible than the last and thus no cracking could occur.... 

Now when it comes to using Liquin this can get a bit contradictory for some, as it's a fast drying Medium, that is, the more one adds the faster the paint will dry. Thus adding more of this medium to successive layers would seem to go against the exact principles that Fat over Lean is based on... However this reasoning becomes null and void once one takes in to account the pliability of Liquin which unlike Linseed oil (which dries hard ) stays pliable after it dries.

Check out how I applied Liquin's unique properties for a sort of Venetian style painting technique here...