Open and honest; also unposed in photography.
Brightness before frankness
Simplified path. The puzzle showed the main steps; the full route is being checked.
Latin
candēre
‘To shine or gleam’
into English: the shining verb forms a bright-or-white adjective, reaching English through Latin and French.
English
candid
‘White’
the early color sense contrasts with modern honesty; favorable attitudes also occur in the older Latin range.
English
candid
‘Open and honest’
The older white sense survives as a dated literary use. French candide and Latin candidus lie behind the English adjective.
The first English adjective record points to white; the French and Latin brightness history is explicit.
Latin candidus belongs with candēre, to shine or gleam.