What is the No.39 gray gradient background paper?

Shanghai: Starlight Photography Market Turn left on the escalator on the third or fourth floor of Xietu Road, Luban Road. There is a relatively large storefront. There are background tracks, background paper and so on. It's for sale. I bought it there. The easiest skill to master when taking photos of collections is to use background paper to create a cleaner atmosphere. The background color should not be too bright, so as not to stand out too much and grab the line of sight. Some Tibetan friends like to take pictures of their collections against the background of warm velvet and blankets to set off their treasures. In fact, this is a big taboo when shooting a collection. The chaotic colors set off the collection, destroying the outline of the collection, and the large-scale color reflection is easy to make the cultural relics fade. In addition, the feet of cultural relics are intertwined with fabric fibers, which even the later computers can't handle. Gray is a universal color, which can be matched with cultural relics of any color. Using gray gradient background can avoid the problem of inaccurate exposure. This is because the metering system of the camera is designed with the gray scale of 18%, and the gray scale is the necessary guarantee for accurate metering. This is also the reason why photographers use the gray board to measure light during important shooting. All-gray background is dull because of the lack of change, so all major auction companies use gray gradient background paper without exception. Photograph the legend of the collection with gray gradient background paper.