An electrowetting element (2, 202) comprising: a first fluid (11, 211); a second fluid (12, 212) immiscible with the first fluid; a first support plate (5, 205) and a second support plate (6, 206), the first fluid and the second fluid located between the first support plate and the second support plate, the first support plate comprising: a first support plate surface, at least one of the first fluid or the second fluid in contact with the first support plate surface; a substrate (7a, 207a) having a substrate surface; an electrode (17, 217), the first fluid and the second fluid switchable to a first configuration with a non-zero voltage applied between the electrode and the second fluid; a ridge (28a, 28b, 128a, 128b, 228a, 228b) comprising a substantially parallel ridge surface substantially parallel to the substrate surface and a sloping ridge surface angled relative to the substantially parallel ridge surface, wherein an interior angle (44a, 44b) within the ridge between a plane of the substantially parallel ridge surface and a plane of the sloping ridge surface is greater than or equal to approximately 135 degrees, or is between approximately 135 degrees and approximately 160 degrees; and a wall (21a, 21b, 121a, 121b, 221a, 221b) located at least partly on the substantially parallel ridge surface, wherein the wall is located along at least part of a perimeter of the electrowetting element and has an inner surface (34a, 34b, 234a) within the electrowetting element. a first fluid (11, 211); a second fluid (12, 212) immiscible with the first fluid; a first support plate (5, 205) and a second support plate (6, 206), the first fluid and the second fluid located between the first support plate and the second support plate, the first support plate comprising: a first support plate surface, at least one of the first fluid or the second fluid in contact with the first support plate surface; a substrate (7a, 207a) having a substrate surface; an electrode (17, 217), the first fluid and the second fluid switchable to a first configuration with a non-zero voltage applied between the electrode and the second fluid; a ridge (28a, 28b, 128a, 128b, 228a, 228b) comprising a substantially parallel ridge surface substantially parallel to the substrate surface and a sloping ridge surface angled relative to the substantially parallel ridge surface, wherein an interior angle (44a, 44b) within the ridge between a plane of the substantially parallel ridge surface and a plane of the sloping ridge surface is greater than or equal to approximately 135 degrees, or is between approximately 135 degrees and approximately 160 degrees; and a wall (21a, 21b, 121a, 121b, 221a, 221b) located at least partly on the substantially parallel ridge surface, wherein the wall is located along at least part of a perimeter of the electrowetting element and has an inner surface (34a, 34b, 234a) within the electrowetting element. a first support plate surface, at least one of the first fluid or the second fluid in contact with the first support plate surface; a substrate (7a, 207a) having a substrate surface; an electrode (17, 217), the first fluid and the second fluid switchable to a first configuration with a non-zero voltage applied between the electrode and the second fluid; a ridge (28a, 28b, 128a, 128b, 228a, 228b) comprising a substantially parallel ridge surface substantially parallel to the substrate surface and a sloping ridge surface angled relative to the substantially parallel ridge surface, wherein an interior angle (44a, 44b) within the ridge between a plane of the substantially parallel ridge surface and a plane of the sloping ridge surface is greater than or equal to approximately 135 degrees, or is between approximately 135 degrees and approximately 160 degrees; and a wall (21a, 21b, 121a, 121b, 221a, 221b) located at least partly on the substantially parallel ridge surface, wherein the wall is located along at least part of a perimeter of the electrowetting element and has an inner surface (34a, 34b, 234a) within the electrowetting element.