Early Denby hunt jugs were salt glazed: mostly with the standard darker top but very early examples can be very light in colour. Some time in the second half of the 19th century (1860s?) the distinctive “Denby Colours” scheme was adopted and maintained. This was Denby's equivalent of “Bristol Glaze” with a brown coloured glaze on the upper section and an uncoloured glaze on the lower section. The 1960s reproductions of early Denby models are described as having an imitation salt glaze finish. In the case of the reproduction reform flasks this can be fairly convincing - fortunately they are well marked.
Denby Colours are hardly exciting but even worse are the completely uncoloured examples. Off white jugs with standard sprigs have been seen in 1, 1.5 and 4 pint sizes: presumably others exist. These are most probably 20th century and may date from the World War 2 period. (Click for image).
Uniformly mid brown saltglaze is also known, again uninspiring but better than all white. (Click for images)