The two grey neutrals split this size between them and neither crosses. Plain slate at 31mm is built on the six Everose references and on no yellow or white gold one; dark grey, the other grey the range makes, is built on the yellow and white cases and never on Everose. A buyer choosing a grey dial at this diameter is therefore choosing a metal at the same time, whether or not they intend to. That is not true of the pale neutrals, which reach every metal the size is built in, and it makes the greys the clearest instance of the catalogue allocating a dial by case temperature rather than by preference. Reference 278275 is the 31mm Datejust in Everose gold, carrying a fluted bezel, and this configuration pairs a plain slate dial with applied gold markers, fitted to a President bracelet.
The case is solid Everose gold at thirty-one millimeters with the fluted bezel cut into the metal itself. The dial is slate, a mid-grey with a sunray finish that sweeps between light and near-black as the wrist turns, and it is the only cool surface on the watch. Applied gold markers stand at the hours, and against a grey ground they have real separation, which is not true of the rose dials this reference also builds. That is the practical difference between a matched ground and a neutral one: on rose the markers work by shadow, and on slate they work by contrast. That difference is worth understanding before choosing between the two, because it decides whether the watch can be read in a dim room or only in a bright one, and it is not a distinction any listing photograph will make clear. The President bracelet is semi-circular three-piece links in the same gold, rounded across their width, and it is the only bracelet the reference offers. Because everything except the dial is warm metal, the watch divides cleanly in two, with a cool disc under the crystal and gold everywhere around it, and the fluted rim sits directly at that boundary, which is where the contrast is strongest. A fluted rim reads as a ring of alternating light and shadow rather than as a solid band, so the transition from cool dial to warm metal happens across a broken edge rather than a clean one, and the dial appears to sit slightly deeper in the case than it does on a smooth-bezel watch.
Hours, minutes, running seconds and a date changing in one step at midnight rather than easing into the day that follows. The self-winding movement in the 31mm case holds roughly fifty-five hours of running time, matching the 28mm references rather than the 36mm ones, which use a movement of their own. The date sits at three under a magnifying lens, and against a mid-grey ground the window is visible without being dominant, which places this dial between the rose grounds, where the date is the brightest thing on the face, and the darker ones, where it competes with everything. Applied markers are read by position rather than by identity, so the time comes from the angle of the hands. On a sunray ground that arrangement performs unevenly, since the surface behind the markers is constantly changing value and there is an angle at which the two match, but the tonal gap between gold markers and a grey ground is wide enough that this rarely lasts more than a moment. What a sunray finish adds in exchange is that the dial is never the same twice: a flat grey would give the markers a constant background and a duller watch, and the sweep is the reason slate is worth building at all when the range already makes white.
Slate is one of the broadest grounds the catalogue builds, appearing at 31mm, 36mm, 37mm, 40mm, 41mm and 42mm, and its marker treatment changes at nearly every size; at 36mm and 41mm it takes the Roman set with a baton at nine that belongs to this ground alone across the whole range. At 31mm it takes applied markers, on the six Everose references, and it is also built set with diamonds on the same six, in the oversized six arrangement that exists at this diameter and no other. So slate arrives here two ways while dark grey arrives on the cool cases two ways, and the two greys mirror each other exactly without ever meeting. Within this reference slate is one of nine grounds across eleven configurations, seven of which carry stones, and it is one of only two unset dials that are not rose, the other being white. The reference is one of five solid gold Datejusts at this size, all President-only, and 278285RBR is the same case with a set rim carrying the identical roster. Between the two of them a slate dial in solid Everose at this size exists in exactly two watches, one under flutes and one under stones, since the bracelet is fixed and there is no second marker arrangement to choose.
This suits a buyer who wants a solid gold watch that is not warm all the way through. Slate is the one ground on this reference that neither matches the case nor opposes it outright, so the watch has a genuine internal contrast without any of it looking like a decision to be colorful. Against the rose dials it is legible where they are subtle; against the white it is softer and less declarative. Anyone who wants the same ground with stones should take the set version, built here with an oversized six that this reference also carries on aubergine. Anyone who wants more contrast should take the white. And anyone who wants a grey dial in a yellow or white gold case will not find slate there, since at this size that ground belongs to Everose alone, and the nearest equivalent on a cool case is dark grey, which behaves differently under gold markers.
