What is the difference between the measure words 面 vs 张?

Question

Apparently both are measure words for flat objects, are they interchangeable or is there a difference to the types of flat objects they are used for?

Answer 1

They are both relative to the object thin and flat.

面 is connect with something vertical,realistic.一面镜子，一面墙，一面锣。

张 is connect with the thing horizontal.一张纸，一张相片，一张邮票。

In addition, 张 is connected with the action which needs to open, like 一张嘴，一张弓, 一张网。

Answer 2

面 is normally for something in vertical position, like 一面墙， 一面镜子， 一面旗帜。

张 is normally for something in horizontal position, like 一张报纸，一张饼， 一张网。

张 could be a measure word for something other than flat objects, like 一张嘴， 一张桌子，一张弓。面 doesn't have this kind of usage.