The application of gilded lança characters to constrastingly darker metal objects was particularly popular in the Qianlong reign. This was a period in Chinese history when Lamaism enjoyed considerable imperial favour, and thus lamaist inscriptions were applied to a variety of objects, both religious and secular. Metalwork pieces with this type of decorative gilt inscription included not only altar vessels, such as censers like the current example, but also items such as imperial helmets like the one worn by the emperor in the famous Castiglione portrait of Qianlong on horseback. This helmet was exhibited with the portrait in Macau in Qing Legacies: The Sumptuous Art of Imperial Packing, Macau Art Museum, 2000, pp. 200-201, no. 100.
The use of frogs as the feet of the censer is unusual, but brings to mind the frogs in similar stance that form part of the famous seismograph devised for the Chinese Court by the Chinese Royal Astronomer Chang Heng in the Eastern Han dynasty, 2nd century AD. This device, which detected earthquakes and their direction, comprised a large bronze vessel with an internal mechanism which signalled an earthquake by causing one of eight dragon's heads to drop a bronze ball into the mouth of one of the eight frogs seated beneath, see R. Temple, China - Land of Discovery and Invention, Patrick Stephens, Wellingborough, 1986, pp. 162-6.