Question: "Why do we change colors of vestments and Icon stand covers? I know these are done according to church practices. However, could you explain each color's meaning and when they are changed?"
In the Typikon, which is a text that lays out how the services are supposed to be done, there are only references to light and dark vestments. The use of a color scheme came into use in the Roman Catholic Church in the early 1500's, and then were incorporated into Russian practice, though with changes. Eventually, these colors have been more or less adopted by other local Orthodox Churches, but not always used in the same way.
There are too many different practices to try to encompass all of them in a short article, but here is the color scheme generally used in the Russian Church:
1. Gold is generally used for lower-rank feasts of the Lord, and on weekdays and Sundays outside of Lent that do not have another seasonable color.
2. Blue is used for feasts of the Mother of God and the bodiless hosts, because blue is the color of the sky, and the Theotokos is the Queen of Heaven. Blue is also used for the feast of the Meeting of the Lord, which is in some sense a feast of the Lord, but also a feast of the Mother of God.
3. White is used for certain great feasts of the Lord: Nativity, Theophany, Pascha, Ascension, and Transfiguration.
4. Red is used for feasts and days commemorating the Cross of Our Lord, the Martyrs, and also for the Nativity Fast, the Apostles Fast, and the beginning of the Dormition Fast. It is also used on Holy Thursday, which commemorates the institution of the Eucharist.
In Russia, it has become the usual practice to wear red throughout the Paschal season. This was originally a Moscow practice, but in post-revolutionary Russia, it has become the norm throughout Russia. In the Russian Church Abroad, we do not follow this practice, but continue to wear white. However, because of this practice, in Russia, they wear a bright red for Pascha, but a darker red on all the other occasions that call for red.
Red obviously represents the Blood of Christ and of the Martyrs. When used during a fast, it is used as a darker color, but not so dark as the purple and black of Lent. For Pascha, it is because the Russian word for red (красная) is the related to the word for beautiful (красивая).
5. Green is used for Lazarus Saturday, Palm Sunday, and Pentecost. In the case of Lazarus Saturday and Palm Sunday, it is related to the color of the palms and the leaves on the branches strewn before the Lord on his way from Bethany to Jerusalem. For Pentecost, it represents the new life of the Spirit.
6. Purple is worn on Saturdays and Sundays of Great Lent, and also on some minor feasts during Lent. It represents the royal purple of Kings, because this is a season dedicated to Lord.
7. Black is worn on most weekdays of Great Lent, because black is a color of mourning, and during this time we weep over our sins, in preparation for the joy of the Feast of Pascha.
The color of a feast is usually worn not only on the day of the feast, but on the forefeast and during the afterfeast, and on the apodosis.
These same colors are also used for different classes of saints, but there tends to less uniformity and more variety of practice. There is a chart that is fairly complete, which notes the usual practice in ROCOR, but also notes some of the more common differences in Russian practice. See: Colors of Liturgical Vestments (from the St. Innocent Liturgical Calendar)
