Kavyalankarasarasamgraha 7.12

7.12

chāyā śobhā /
yatra saṃdehābhāve 'pi saṃdehasyopanibandhe sati na pūrvavadupamānādupameyasya bheda upanibadhyate kiṃtarhyabheda eva saṃśayacchāyayā /
tathāvidhasya copanibandhasya phalamalaṅkārāntaropajanitā saundaryapratipattiḥ /
yadāha---dhīṣvalaṅkārāntaracchāyāṃ kṛtvā iti /
tatrāpi saṃdehālaṅkāraḥ /

'Luster' (chāyā) means beauty.
Where, even in the absence of doubt, there being a composition of doubt, a difference of the subject of comparison from the standard of comparison is not composed as before, but rather only a non-difference under the guise of doubt;
and the result of such a composition is the apprehension of beauty produced by another ornament.
As he says: 'producing in minds the luster of another ornament'.
That too is the ornament of doubt.