This first attempt to periodize the history of advertising in modern Shanghai capitalizes on the findings of the chapters 2, 3 and 6 of my dissertation. Relying on municipal archives, professional literature and any material documenting outdoor advertising and the advertising profession in general, it offers to periodize the institutional, business and social history of advertising in modern Shanghai foreign settlements - that is, the "hidden" face of advertising history, usually neglected by cultural studies devoted to advertising. In this timeline, the social history of advertising is embedded in a wider political and economic context, at various scales (from China to world history). 

This multiscale timeline is based on two main concepts: timeslices (periods of time) and timeframes (spacetime scales or dimensions).

By timeslices, I simply mean "periods of time." As far as Shanghai advertising is concerned, I precisely refer to the five main periods identified in the introduction of the dissertation : before 1919, 1919-1929, 1930-1937, 1938-1943, post 1943. The dividing lines between timeslices appear to be blurred and permeable boundaries, rather than clear-cut hermetic borders. Their approximate datation suggests gradual transitions rather than radical abruptions. Main boundaries result from the overlapping and intersections of several timeframes. 

By timeframes, I mean spacetime scales or dimensions. To put this another way, by using the notion of "timeframe", I intend to examine the history of advertising in Shanghai through various lenses, at various scales of space and time. My ultimate goal is to offer a multiscalar periodization of advertising in modern Shanghai, embedded in various frames. For that very purpose, five main timeframes may be identified, each one following its own periodization and rhythmic patterns: 

1. Emergence of the advertising profession in Shanghai and China (1905-1956). This timeframe may be started with the erection of the first problematical hoardings round building in course of construction in the International Settlement (A.G. Hickmott), and closed with the forced restructuration of the advertising profession in 1956 at a national scale, which drastically reduced the number of advertising agencies from about to sixty to only four giant companies, each one dedicated to a special branch of advertising (press, outdoor, radio, transportation). 
2. Municipal policies towards advertising in Shanghai foreign settlements (1905-1943). This frame started with the first informal deliberation following the erection of the first standard hoardings, including the first census of advertising spaces in 1914, the establishment of the first scale of fees in 1914, revised in 1924, the creation of the first authorized zone for advertisements in the French Concession in 1926, revised in 1927, 1929, later municipal regulations regarding hoardings in both settlements (between 1929 and 1930), shop-signs and posters in the French Concession in 1938. This timeframe ended with the Cleansing Campaign launched in April 1943, the last census of advertising hoardings in the International Settlement in May 1943, a few weeks before the official abolition of foreign settlements (July 1943).
3. Shanghai local history (1842-1949/1951): This timeframe started with the Nanking Treaty (1842) and the establishment of the British Settlement (1843), and may be ended either with the entering of Communist troops in Shanghai in 1949, either with the closure of the latest large foreign newspaper in Shanghai (North China Daily News) in March 1951.
4. Late Qing-Republican China national history (essentially examined through the lenses of China relations with foreign powers) (1839-1949). This frame may be started with the first Opium War and ended with the proclamation of the People Republic of China on October 1, 1949.
5. World history, in connection with Chinese and global advertising history (1839-1956). This timeframe includes major political and military events, economic conjuncture (crisis, boom and depression) that are liable to influence advertising, and the history of advertising business in other countries (especially in the United States, considered as the "model" country for modern advertising and the "cradle" for the birth of the advertising profession at the turn of the 19th-20th centuries. 

By embedding these five frames, this multiscalar timeline is expected to reveal connections between events within the same frames or belonging to different frames, to suggest interactions, either influences, coincidences, overlappings or gaps between timescales and the events they contain, as well as spatial and temporal circulations between the same.

In "Chronozoom", timeframes are materialized by what is refered to as "timelines" by this web application. "Chronozoom" may be supplemented by another web application called "La Ligne du temps". While "Chronozoom" is quite an efficient tool to build multiscalar timelines; by embedding "timelines" (what we personnally refer to as "timeframes"), as well as exhibits and tours based on visual materials, it is very disappointing in terms of placing events within timeframes (timelines). It is much less relevant for connecting events within the same timeframe or from one to another timeframe. To sum up, although it proves a powerful tool to create "multiscalar" timelines displaying visual materials, it is of little relevance for historians concerned with building serious timelines based on either fuzzy or precise datation. 

Conversely, "La Ligne du temps" allows to create linear timelines divided into timeslices, based on more or less approximate datation. Although it has proved an efficient tool for placing and connecting events, it has serious limitations in terms of embedding timeframes and correlating various scales of time and space. The only way to create such timeframesis is to use the "thematic bands" function, which consists in isolating frames as individual colored "bands". Yet in doing so, one cannot actually embed the bands. "Thematic bands" remain juxtaposed and all have to follow the same unique temporality. They cannot obey to their own periodization and rhythmic patterns. Last, contrary to "Chronozoom", "La Ligne du temps" eventually does not allow to include our own visual materials.