a) three generations

This shows three generations with the dam on the left, the son in
the middle and the grandaughter on the right. All three have pleasing
expressions, though they are all slightly different.
The dam has a very femine head with an excellent expression. Her head is balanced and shows a proper clean wedge with a good stop. Correct eyes and ears add to the correctness of her overall look.
The son shows a masculine head with a good full muzzle balanced with the backskull. He has a little more fill between the eyes, in the stop area. This does not stop him from having a pleasing expression.
The grandaughter displays a nice head which for a bitch may be a tad
heavier than desired. She has a round, very full muzzle and shows slighly more fill in the stop area than her grandam. Her head is balanced but is a tad shorter than her grandams.

b) sable rough male

c) sable rough male

Very pleasing expression due to correct
eye shape and placement, ears, as well as other head attributes.

A perfectly acceptable expression in a Collie
with a slightly different head features than the previous one. Some of this is due to differences in the stop as well as the shape of the wedge of each dog's head. The difference in the color of each dog's coat could also be affecting expression, a darker mask vs. a lighter mask.

d) blue merle rough bitch

e) tri-colored rough male

An acceptable expression for this Blue
with a 'split face'. This happens to be an even split which also helps the expression.

A perfectly acceptable expression which
looks different from other tri heads shown
due to color pattern. Head is masculine, balanced, coffin shaped wedge obvious, ears
and eyes appropriate.