I want to ask an old-timer or a professional or a photographer-

In fact, the proportion of photos is related to the photos cut out. The ratio of developing your own photos is not necessarily what it is according to the requirements of different photos, but the studio is more common at 4: 3 or 3: 2. (It was difficult to find a photo studio in the early days, and most fans made their own films, so the proportion commonly used in this photo studio in the early days can also be ignored. )

When color photography just emerged, it was a 120-frame double-mirror camera. If not cut, the film produced is usually 6: 6.45 or 6: 7. This is just a general situation, and many times it is not this ratio. For example, there is also a 6: 6 approximate square. There was also a ratio of 5: 4 in this period, but it generally appeared in a 45-page camera with a larger frame than 120 (according to the current statement, it can be understood as two files higher than Quan Huafu), and its popularity was relatively low.

Although color photos began to rise in the era of 120, its popularity began only after the appearance of 135 camera. At this time, the ratio of the negative became 4: 3, which has been used ever since. This ratio of 1: 0.6 18 is the golden ratio. This proportion is more beautiful from an aesthetic point of view, but it is also obtained through cutting, which requires higher cutting requirements. If it is an artistic photo, it is possible to do so, but it is usually an approximate value, which is the 3: 2 I said at the beginning.

Personal experience, all by hand. I hope I can help the landlord