As we prepare to go into pre-Lent (can it already be here?), a few changes liturgically to note:
Beginning with the Divine Service for Septuagesima, the plaintive Tract replaces the joyous Alleluia and Verse.
Beginning with Ash Wednesday, the Gloria in Excelsis (or any Hymn of Praise) is omitted from the Divine Service.
Beginning with Judica, the Gloria Patri is omitted from the Introit.
Note that the Gloria in Excelsis MAY be used on Holy Thursday, if the service does not begin with the Service of Corporate Confession and Absolution.
Now the usual discussion of the color mess. First, remember that uniform use of the colors is relatively late. Read through Stiller's work on Leipzig at the time of Bach and you'll readily see how different from our current expectations the color scheme in use at the time was! But if we pay attention to the rubrics of our hymnal, then we have the following:
Pre-Lent - Green, with the Epiphany Preface continuing in use (see, Altar Book, pp. 862-865).
Ash Wednesday - Black or Violet with the Lenten Preface (see Altar Book, p. 867).
Invocabit through the week of Judica - Violet with the Lenten Preface (see Altar Book, pp. 868-875).
Palmarum through Holy Wednesday- Scarlet or violet with Holy Week Preface (see Altar Book, pp. 876-880).
Holy Thursday - White, scarlet or violet with Holy Week Preface (see Altar Book, p. 881).
Good Friday - Black (if paraments are used, but see note on p. 511 "the altar remains bare, having been stripped on Holy Thursday") with Holy Week Preface (see Altar Book, p. 883).
Easter Vigil- Easter Wednesday- White or gold with Easter preface (see Altar Book, p. 885-891).
Certainly there is variety in how parishes choose to follow these particular rubrics. There are places that follow the one-time Roman custom of Pre-Lent being violet. There are places that insist on the White for Maundy Thursday. Here at St. Paul's our actual practice accords with the rubrics cited above, with these choices: violet for Ash Wednesday; Scarlet from Palmarum through Holy Thursday; Bare for Good Friday; and Gold for the Easter feasts. We do use the Corporate Confession option both to start and end Lent: on Ash Wednesday and on Maundy Thursday.
It seems each year that these questions get discussed around the blogosphere, so that's a quick reference guide if you're looking for the actual rubrics of our current rite. They're not divinely inspired; you may well disagree with the wisdom of some of the choices; but they are the guidance our Synod offers us, for what it's worth.