A couple of years ago, I researched and posted an article on the use of penitential colours for the Seasons of Advent, Lent &c. That post may be read here and here, so I don't intend to rehearse its findings.
Instead, always most interesting, an historic work of art to illustrate the practice of our forebears. This work (adjacent) was painted by an artist known as the Master of Osservanza in the year 1440 and depicts a Low Mass being offered at a side chapel in the Siena Cathedral (Italy).
Some observations. The chasuble being worn by the celebrant is violet: in other words, much the same colour as the flower "violets". It is a blue-ish colour, not purple and it is not too dark either. The chasuble is the full conical shape and is ornamented with a simple column-orphrey of dark fabric (possibly even black). Most likely, the front of the chasuble would have been decorated with the familiar "tau". The celebrant is wearing decorative apparels on his alb and amice, which match the colour of the chasuble's ornament. That is a very typical practice of the Mediaeval period. Note, too, the very full folds of the alb.
We see, also, that the boy assisting the celebrant is wearing a full-length surplice, according to the style typically found in Renaissance Italy. Those who claim that such surplices are "Church of England" practice should note this well.
Lastly, the altar itself. It is clothed in a dark antependium or altar frontal, ornamented with scarlet red. On the altar is a Crucifix and a single candle. Although it may seem peculiar that there is but a single candle instead of a pair, it might be remarked that not until the 16th century was it a usual practice to have a pair of candlesticks on an altar.
Lastly, the altar itself. It is clothed in a dark antependium or altar frontal, ornamented with scarlet red. On the altar is a Crucifix and a single candle. Although it may seem peculiar that there is but a single candle instead of a pair, it might be remarked that not until the 16th century was it a usual practice to have a pair of candlesticks on an altar.
Click on the image for an enlarged view.