When we scan lines, we generally look first at the tension between the metre and lexical stress. I will refer to this pattern of lexical stress as the lines’ ‘resting state’ prosody or RSP. (I use the phrase to include such prosodic qualities as we may also want to take account of at the phrasemic and syntactic-phrasal level too.) By ‘resting state’, I mean such prosody as already inheres in the language (a) before any larger contextual sense has been derived and performed and (b) before any metrical frame has been diagnosed and projected into the verse.
Wherever the underlying metre is not immediately apparent (i.e. whenever the line is in either loose or light metre), the RSP of several lines will indicate or confirm the metrical template on which they converge. However tight or light, a line works to an identical underlying metrical frame; therefore metre is always marked in exactly the same way. My rough procedure is as follows. The metre is ‘decided upon’, and then indicated by marking strong positions with a /, and marking the position or medial point of the weak placeholders with an x or -x-; the metre is then compared to the actual line’s lexical stress; points of disagreement are registered; and then a sense-stress scansion is conducted. The result is a blueprint for performance which can and should be open to a variety of competent interpretations.