Colour makes for difficult communication.

Case in point - I speak from experience here - you go in asking your hairdresser for a nutty brown tint with gold highlights a la Jennifer Lopez, and come out looking gingery blonde a la Nicole Kidman. Paint is another nightmare. I could bore for Britain on the unfathomable nuances of off-whites. My hall cupboard is a graveyard of testers, painted wallpaper squares and half-used paint tins. Rather than exhausting the possibilities of colouriser charts, another approach is to identify a colour, in a friend's home perhaps, but even then there's always a confounding factor: their room faces north, yours faces south; they have it on their floor, but it looks darker on your walls, and so on.

When we get to black, you'd think there would be some clarity, but even this is a crepuscular quagmire of meaning. Reading the description for Blackwood's, the restaurant in Edinburgh's Nira Caledonian, did not prepare me for the gloom that was to greet me. "Designed in a colour palette of black and gold with bold accents of reds and greens, the property exudes romance. A cosy restaurant is lit by the soft glow of a chandelier, while the striking architecture on the street opposite is visible through original sash windows." Now that sounds pretty smart, and it's not that Blackwood's isn't smart, it's just that it's very, very black. Perhaps the designer has taken the Rolling Stones' Paint It Black lyrics a bit too literally. Walking in on a sunny June evening felt like going into a coal mine. The walls are painted black. The wooden shutters over the striking Georgian sash windows are also painted black, not even matt or eggshell black, a particularly uncompromising high-gloss black, and the shutters are closed in an uncompromising, once and forever way, with only hairlines of daylight showing through. Some diners might need a torch to read the menu. This is blackness that wreaks havoc with one's circadian rhythms. The urge to put your head down on the linen tablecloth and snooze is stronger than in a public library reading room. Another set of lyrics come to mind: Let the sun shine in. We get so precious little, don't deprive us further. I asked our affable waiter if they ever open the sombre black blinds; he looked wistful, and shook his head apologetically. Staff must become resigned to a troglodyte existence.

If you don't doze off, the food has quite a lot going for it: good ingredients (the bread is from Peter's Yard, for instance), careful, attentive cooking, a sensibly limited choice. After a complimentary micro-course of Thai fishcakes came deftly made ricotta, pine nut, basil and lemon ravioli whose only fault was that they didn't have quite enough pesto oil to lubricate them, and a reasonable, if slightly too thick, carpaccio of grass-fed beef from Highland cows, with rather too sweet horseradish cream, and frisky pea shoots. Blackwood's uses the latter as a garnish for pretty much everything savoury. At least it's respite from rocket.

A Josper grill brought us fabulously fleshy Scottish lobster napped with garlic butter, and deftly seared rib-eye steak, flanked by a little cocotte of exemplary Bearnaise sauce. A side order of bone marrow cooked on the grill was a melting indulgence: what a flavour. The chips looked over-cooked and brown, but they tasted great and had the crispness of the twice-or thrice-cooked article.

In the puddings department, a frozen nougatine parfait felt dated: too sweet, it hadn't cut cleanly, and its pistachio cream had a fridge taste to it. The dark chocolate fondant, on the other hand, was a star, with its barely contained oozing innards and icy, rather than rich, homemade vanilla ice cream.

If it would lighten up, Blackwood's would be a more attractive option. The staff are good, the location more intimate than larger city centre operations, and deep in the heart of the New Town, there's heart-soaring Playfair architecture on the doorstep. Blackwood's is quite relaxing, in a soporific way. Manageably priced set menus won't raise the blood pressure either. The problem is staying awake.