Chenpi is a sun-dried tangerine peel used as a traditional seasoning in Chinese cooking and traditional medicine for 700 years. In the West, tangerine peels are by-products and rubbish. In China, tangerine peels can be turned into treasure by sun tanning and are even more expensive than the tangerine pulp itself. Chinese people believe that 'the age of Chenpi is worth more than gold", "a thousand years to raise ginseng, a hundred years to get Chenpi'. Tanning is a very important part of Chenpi processing. During the tanning process, the peel is exposed to light and its shape, texture, moisture, and colour change. Lumen printing technology relies on factors such as light and the shape, texture, moisture, etc. of the printed items. The peel on the photographic paper absorbs light during the tanning process, blocking part of the light from reaching the paper, thereby forming an image. Repeating the experiment in chronological order can visualise the process of 'fresh tangerine peel absorbing light and turning into Chenpi'. For my project, I recorded the tanning process of tangerine peels for 16 days to simulate and re enact the formation of Chenpi, and to reflect upon Western and non Western durational and cultural concepts.