It looks like my inquiry is not worded clearly enough.
Consider the sentence:
The already long known phenomenon of bloom, a wrinkling of the tin bath glass surface, produces a greyish haze, related to the oxidation of Sn≤+ to Sn4+. (Moseler et al 2001). The conversion of Sn≤+ to Sn4+ is a necessary but not sufficient condition for the formation of bloom. (Williams and Thomas 1999).
Can we say "already long salient/tangible/noticeable/conspicuous/discernable process"?