There has been much explanation written about the exact details of black and white tie and all its various components but when it comes to hoisery (i.e. socks) there is only sometimes a glancing mention and with no other explanation or rationale, though there are some information in the Black Tie Guide. Here I would briefly explain what sort of socks are appropriate for evening wear.
Firstly, as all will know, evening dress is rooted in Brummell’s stipulation for simple elegance and a simple monochromatic colour scheme of black and white, but sometimes with a subtle hint of colour that is in harmony with everything. Thus, our black tie and white tie dress codes are essentially based on these principles. In the day, we wear every colour under the sun, at night we wear simple yet elegant colours letting the superior cut and details of the coats speak for themselves. We will be mostly indoors so our attentions are to be focused above the waistline and this is why white in these ensembles is restricted to the shirt (and waistcoat and tie), the upper half of the body, and everything else is black. The studs would be often of silver or gold or MOP and these are on the said white shirt (and/or waistcoat; hence why you never see studs on black waistcoats). The buttonhole flower is often a white carnation but could be red or other coloured flowers and it is the only item where colour (other than white, gold or black) is permissible; linking sartorialism and nature. One of the reasoning for this is that the men should not outshine the ladies who would be in fabulous and colourful gowns. It is the yin-and-yang of sartorial courtship.
So, it is therefore required that the socks be black (or mid-night blue if the coat and trousers are of that same colour) in order for them to blend in and be inconspicuous. This is also why one should not wear spats (which are outdoor garments anyway) with evening dress, especially white ones, nor two toned shoes with coloured galoshes with them. It draws attention to the feet when one should be focusing above. Not only that, it creates an unsightliness with the trouser hem moving about creating various shapes of colour.
One could be forgiven for wearing coloured socks with black tie as it is informal (by my standards at least!), but it is highly inappropriate for white tie as it is the most formal dress code for civilians (almost uniform) and high formality requires uniform precision and so it must be black (or mid-night blue) and nothing else. Wearing coloured socks for white is like wearing coloured socks for a full dress military uniform; it is out of place and not in harmony with the scheme. And it is especially silly if one wears coloured socks with court shoes!
So, what kind of black socks one could wear?
Tradition says it should be silk but there is some leeway here. Given the black would make them inconspicuous, the material would not make much of a point of importance since the primary objective is already achieved. Thus, silk, cotton (which could be mercerised , even wool would be appropriate depending on the climate and needs. They could be plain, ribbed or clocked.
Wool and cotton socks (of whatever length to suit tastes) are fairly easily to come by so I will not go further into this. The only thing I would advise (and this is relevant to all socks) is to have a ‘hand-linked toe’ which basically means the toe cap seam is hand seamed so it is flat and without the excess nobbily protrusion across the top of the toes inside the sock itself which often causes discomfort.
Silk, however, is much more difficult to obtain. There are various sources which I will now highlight.
Half hose refers to the length being below the knee. These would be mid-calf length or calf length. Mid-calf length ones require the wearing of sock garters to avoid them slipping down.
Patra stocks mid-calf length ones in two lengths (the long version isn’t long enough to not use a sock garter with). They are of a good weight being rather thick and are long lasting. At £10.50, they are very reasonable. They are pure silk but with some nylon on the band.
Another place you may get a sheerer pair of these is at Austin Reed (and some other high-end London shops). They are priced at £14.
For calf length socks, there is Gieves & Hawkes. Theirs are much more sheerer than the Patra ones; very light and feel very comfortable, but they don’t last very long if you wear them excessively (one of my friends wore a hole in them after one night!)
At £25 a pop, they would probably be best reserved for a very special event. They exist in the black and the navy/mid-night blue versions. They are 100% pure silk with no nylon on the band. Foster & Son also stock a thicker pair at the same rice but they are mid-calf length version: I don’t know if they stock the calf length version.
If you’re not too fussed about the socks being 100% pure silk, BLEUFORÊT of Paris stock a silk-cotton version in both short and long versions. They are not as sheer as the G&H ones with them being thicker and thus would last longer given the cotton content.
Full hose refers to above knee hose and includes stockings and ‘tights’. These are not necessary for you normal black or white tie but are if you wear breeches for white tie (i.e. alternative court dress). However, in such a case, very long half hose may be long enough to be worn with breeches (such as the very long Bleuforet ones, see above) as long as the bottoms of the breeches cover the ribbed banding at the opening of the socks. (Dress breeches are often made to end just above the calf.)
As far as stockings are concerned, these are extremely hard to come by as no one save those who wear court dress would need to wear them. They need a garter belt to hold them up as they end around a few inches above the knee and so are likely to slip down. Of course, if the breeches are tight enough at the straps they would be held up naturally.
The only place I have found that sells silk stockings for men online is James Townsend & Son in America but they exist in grey and off-white versions meaning you’ll have to dye them black.
If you’re not fussed about getting a vintage used pair, Hobbyswood Militaria have some from time to time (under Non-Military > Clothing, Shoes & Jewellery). Note that they might be a bit worn and have a hole or two that need darning.
As for tights, these can be had via a few places. Ede & Ravenscroft stock some but they are cotton-nylon ones which will not do.
The only other place I have found is UK Tights which make a pair for men but not in 100% silk. These are opaque enough for use with breeches.
I also imagine that Henry Poole would stock silk stockings and/or tights but they probably won’t sell you a pair unless you buy a full court suit from them. I phoned them up once and got no where so I probably have to visit them in person and ask very nicely if they sell any court dress accessories, etc.
To wash silk socks, you have to note that it must be done gently. The more you wash it the drier the silk strands would be. You should hand-wash it carefully and dry it naturally rather than bunging it in a washing machine, especially for very sheer socks. Silk socks with a blend of cotton or the thicker varieties tend to wash better than the thinner ones.
A tip I’ve heard from someone: if the hose are too sheer to the point that it is not black enough and one can see flesh, one might wear ski leggings underneath so it would look jet black. However, this may make one overheat in the summer months so it is best advised to do this in winter.