My skin goes darker in summer, so it's time to start looking for a new face powder. I don't wear foundation, I just need a powder to take away the shine. I've been using Clinique's darkest shade, Stay Brandy, for the past couple of years. When I was growing up in Manchester it was impossible to find, and I had to rely on friends who were visiting London, or even the US, to bring me back a few compacts. Things are different now.

I'm at the make-up section of Selfridges. First stop, Bobbi Brown. The assistant helpfully tells me that their darkest powders, "look much lighter than they are". They do have darker foundations, but I don't want foundation, I want powder, so it's on to Prescriptives. Prescriptives' trademark is that they'll mix any shade to match your exact skin colour. They'd be happy to customise me a loose powder, but there is no tester, so once they start mixing, you are committed, and at £35 a pop I'm not ready to experiment. On to Chanel, where an apologetic mixed-race woman tells me to try Bobbi Brown, Iman or "somewhere like that". Ditto at Estée Lauder. Christian Dior try to flog me a bronzer, and YSL have a grand selection of two powders. The nice woman at Shiseido solves my problem by telling me I don't need anything at all. Flattery is certainly preferable to the blank looks I've got at the other counters, but it's no more useful.

Normal service is resumed at Elizabeth Arden. At Calvin Klein, I try a foundation that is supposed to dry as a powder. The colour is good but it's like wearing an oil slick. BeneFit tell me they're getting one in . . . next week. I try Mac, but the darkest is still too light. The assistant tells me I "wouldn't want to go any darker than that". Actually, I would. To Fashion Fair, the US brand for "women of color". Clearly not my colour, as I'm bang in between two shades. So, it's on to Iman, the brand set up by the supermodel wife of David Bowie. Success! I'm not even their darkest shade. I also buy a lip gloss. On the way home, I can't decide if I'm more pleased that Iman won or annoyed that the others were so disappointing.

Hannah Pool's column on black beauty appears weekly.