Exegesis:

This verse has the function of a parenthetical indication of time.

kai hēmera ēn paraskeuēs ‘and it was the day of preparation.’

sabbaton epephōsken lit. ‘the sabbath was shining forth.’

epiphōskō ‘to shine,’ ‘to shine forth.’ Since according to Jewish custom the new day was reckoned from sunset the verb cannot refer to the shining forth of the sun at dawn; hence it may refer to the custom of lighting lamps at the beginning of the sabbath (Klostermann, Lagrange) or it may be used in a weakened and general meaning, i.e. ‘to dawn,’ ‘to begin.’ The latter is preferable, cf. Plummer.

Translation:

The day of Preparation, or, ‘the day for preparing (or, when people prepare),’ or, if an object and a reference to the occasion have to be added, ‘the day when people prepare things (or, what is necessary) for the sabbath’ (in which case ‘sabbath’ in the next clause is better replaced by a pronominal reference, e.g. .’.., which was beginning,’ .’..; it was about to begin’). Some versions render “day of Preparation” by the term used for Friday; a closer rendering is usually preferable, however, since it reminds the receptor better of the regulations for the sabbath, which play a role in v. 56b.

Quoted with permission from Reiling, J. and Swellengrebel, J.L. A Handbook on the Gospel of Luke. (UBS Handbook Series). New York: UBS, 1971. For this and other handbooks for translators see here . Make sure to also consult the Handbook on the Gospel of Mark for parallel or similar verses.