I did some quick research on this when I was designing a new rosary and wanted to incorporate more color than the usual walnut-stained wooden beads. I have toyed with painting one or two beads on an otherwise stained rosary now and then, and I like the effect. So, here is the symbolism I found for different colors used in the Church:
White: Joy, Purity, Innocence, Virtue, and Holiness (Silver or Gold can be used as a substitute.)
Liturgically, white is the color of Christmas and Easter, the Feasts of the Lord (excepting that of His Passion), All Saints, Feasts of the Blessed Virgin, and Feasts of the Apostles.
Yellow: Renewal, Hope (especially the hope for renewal), and Purity
Red: Love, Passion, The Holy Spirit, and the Blood of the Martyrs (Gold can be used as a substitute.) Red is associated with Feasts of The Lord's Passion, Blood, and Cross; Feasts of the Apostles and the Martyrs; Palm Sunday; and Pentecost
Orange: Courage, Endurance, Strength
Green: Hope, Nature, Freedom from Bondage (Gold can be used as a substitute.) This is the color associated with Ordinary Time.
Violet/Purple: Penance, Mourning Purple is the color associated with royalty, and Rose can be used as a substitute. It is used for the Season of Advent, Septuagesima, and Lent; Vigils; and (along with Black) Good Friday.
Brown: Poverty, Humility, Earth, Monasticism
Black: Mourning, Death Black is the color employed on All Souls Day and for Masses for the dead, and can be seen (in addition to Volet/Purple) on Good Friday.
Blue: Grace, Good Health In its Lapus Lazuli hue, blue is always associated with The Virgin Mary and the Immaculate Conception.
How I use this knowledge in making rosaries is now the question. I don't want to over-use the colors; for me, the natural tone of the wooden beads, enjoying the grain of the wood, the satin texture of the sanded and stained piece--those are too important to just pain over. However, when used as an accent, particularly where the symbolism of the color is important to the person for whom the rosary is intended, a judicious amount of color could be beautiful and meaningful at the same time.
For instance, if I were making a rosary for one of my Franciscan friends, I could paint each of the five "Our Father" beads brown, as it is associated with Poverty and Humility, both essential values in St. Francis' life. Additionally, painting one of the three "Virtue Beads" a Lapus Blue could be used to indicate Francis' devotion to the Virgin Mary.
