A Masters Hand!!!

There is only one main difference the backgrounds now days are line drawn under the paint back when these were made the backgrounds were painted free hand and the cels were made around what the background artist painted, Now days the backgrounds are a second thought and are layed out before any cels are made to match the cels from the scene that they are in.
If you look real close to your newer backgrounds most of the time you can see the drawing under the paint, On the older backgrounds you will not see this line drawing under the paint as the background artist took more pride in there work and would never use a line drawing on the same board.
Thats why sometimes in the older shows the cel looks like it is floating above the ground and not in contact with the ground.Old school of thought.
Now days all the art is layed out before any cels or backgrounds are even made, It makes for a better looking scene but you lose the artist touch that made each show have it's own style.
You used to be able to tell what artist did the shows artwork by his style but now days it can be hard to tell, And I think that is a shame and a loss to us all.
Some of the newer artists are just as good but are not given the free hand as in the past.

Roy