As far as I know, -webkit-font-smoothing doesn't change weight, it changes rasterization. What you describe in Photoshop also isn't weight, it's rasterization.[

As far as I know, -webkit-font-smoothing doesn't change weight, it changes rasterization. What you describe in Photoshop also isn't weight, it's rasterization.[1] It is true that these settings control the rasterization, but it is also true and a well-known problem that different rasterizations (and in particular, the default rasterizations on different platforms) can result in different apparent font weights. As you noted in your longer top-level comment, this doesn't actually seem to be the problem the original author encountered here, though.