I also note that Sydney's Antarctic photos, like Craig Potton's in his recent show, show the snow and ice as pale grey. For a camera to register detail in the lightest areas, it must be set to underexpose - to register bright white as a pale grey. This can be modified in the printing stage, by overexposing (or "pushing") to turn this palest grey back to white. Of course, the more the image is pushed to white, the more detail is lost. Potton and Sydney have both opted for truth-to-detail rather than trying to replicate the blinding whiteness that must be such a feature of being in the Antarctic.