Like a line of spilt Indian emulsion (14)

'spilt indian emulsion' is the definition.
I don't know anything about this answer so I cannot judge whether this works.

'like a line of' is the wordplay.
I cannot quite see how this works, but
'a' is present in the answer.
'line' could be 'l' (used when specifying particular lines from a poem) and 'l' is found in the answer.
'of' could be 'o' and 'o' is found within the answer.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?