Conventions of techniques: seamless and continuity

 Seamless:
Classic continuity editing of Hollywood is editing that aims to be invisible.
Good continuity editing shouldn't draw attention to itself  this is what leads us to the term of reference 'seamless'.
To be seamless, cuts should take on an invisible quality about them, the viewer should not notice them. To be seamless continuity in terms of all elements of mise en scene and all elements of action in the frame should be preserved perfectly from one clip or take to the next across the cut. Any mise en scene element such as a prop the position of which changes ironiously across a cut breaks continuity and last leads to editing which is not seamless any unit of action that doesn't match properly across a cut also breaks continuity and this again leads to editing which is not seamless.

Continuity:
Continuity editing is the dominant style of film editing in the western world and more broadly in most cinematic culture throughout the rest of the globe. Its purpose is to 'smooth' over the essential discontinuity of the process of editing and to establish a logical ilherance
between successive shots in a sequence. What we mean by this is that the very act of cutting so that there is a change of any kind whatsoever between to shots, even cutting into the same stretch of footage and removing as much as one frame, is a detraction from the continuous progression of a piece of action in real time. If we cut from one angle of action to another the break from the continuous action of the first take is more significant. If we cut forwards in time the break from the continuous first take is more continuous still.

Continuity editing is a process which attempts to make such deviations from the continuous real time action of a single stretch of footage as inconspicuous as possible. Editors achieve logical coherence by cutting to continuity where the emphasis is on smooth transition of time and space.

In the extract from avengers, we witness a fight between Thor and Hulk and are provided a good example for successful continuity editing which is seamless in nature and unsuccessful continuity editing which is not seamless. Up until 0:22 seconds matches of action are good with limbs being in complimentary positions across cuts following the the momentum
of the movement of the two characters. The cut between 0:22 to 0:23 marks a break in good continuity at the end of the shot which finishes at 0:22 fore arm and hand are lower down more towards the underneath of the hulks fore arm. At the beginning of the tape which commences at 0.23 Thors hand and fore arm are higher covering more of the hulks arm with no motion or momentum rational for this change of position. This lack of action match emphasizes the discontinuity and fails to achieve seamlessness