The trend of wearing white on Yom Kippur, at least a bit of white, has been spreading in recent years.
Back in the days of the Temple, the High Priest dressed in white linen on Yom Kippur.
In some congregations, a white kittel is worn by congregants. Some say only married men should wear a kittel; others have different practices. Kittels are quite commonly worn by clergy of various traditions. The kittel is a sort of robe worn over regular clothing, and is usually belted.
Of course, our Sifrei Torah are now wearing white, as is each shulhan in the building!
Many contemplate beginning the new year in total purity, with the proverbial clean slate, as the impetus behind wearing white. White is both the absence of color (in subtractive color mixing) and the presence of all color (in additive color mixing). The Shekhinah is described as glowing white light with diaphanous white textured presence. Of course, this image is also sometimes ascribed to angels as well. (Alternatively, some say each angel has an individual color and maybe also an individual aural tone; this is an in-depth exploration I’ve been working on for a long time about angels for this column. But we digress.)
There is also a long-standing tradition not to wear leather on Yom Kippur, possibly deriving from leather’s association with high status and luxury. Eschewing leather shoes indicates a further humbling such that we would not be so haughty as to walk on another animal. All are equal before God, and we should be humbled in light of judgment (by God and by ourselves), so the leveling thus is also reflected in this parallel practice.
From a different perspective, when we pass away our bodies are dressed in white linen shrouds (with no pockets, as you can’t take it with you!). Thus the reminder that death looms over all of us can be helpful in getting us to “serious up” in our assessment of our thoughts, words, and deeds.
On erev Yom Kippur, at Kol Nidre, we also wear tallitot, prayer shawls, this being the only time in the year when we do so in the evening, because of the holiness of the day. Remember also on Yom Kippur day to wear pockets for your tissues for Yizkor.