1. Introduction

Hollywood films of the 1940s-1960s experienced the baptism of the war years and the impact of the post-war economic boom, showing a vigorous yet diversified development. During World War II, the American film industry dominated the world cinema scene and was famous for its high output, high quality and multi-genre films. At the same time, films were no longer only satisfied with the function of entertaining the public, but also took on more tasks of inspiring people's morale, propagating patriotism and guiding social trends. After the war, with the rise of new media such as television, Hollywood had to make a series of internal changes and innovations. Musical films, film noir, and other genres came on the scene in turn, and the works that emerged during this period recorded the transformation of the industry, as well as reflecting the values and aesthetic trends of society at the narrative and aesthetic levels. André Bazin's theory of cinema places particular emphasis on the power of film as a reality representation, its function as a record of history and social reality. Traditionally, cinema has been seen as a representation rather than a reproduction. However, Bazin argued that the true revolutionary nature of photography and, by extension, film technology lies in its objectivity — its capacity to preserve reality as faithfully as possible and to record it — that is, its ability to capture the imprint of the real world to the greatest extent [1]. Thus, Bazin provides an interpretative framework for film studies that combines documentary with subjective audience perception. Based on Bazin's theory, this study intends to start with the film's reproduction of history and reflection on social context. On the one hand, it explores how the film reconstructs or restores specific historical scenes and social atmosphere at the narrative level; on the other hand, it pays attention to how the creators are affected by the socio-political, cultural and other objective environments in the process of film production and distribution. Through the case studies of Casablanca (1942) and Singin' in the Rain (1952), it can be shown how Hollywood used narrative elements and genre conventions to capture and reconstruct history and social mentality.

2. André Bazin's Film Theory and Historical Reproduction

André Bazin, an influential figure in the history of French film criticism, linked the nature of cinema to photography. He believed that photography is an impression of the world, and therefore it has a natural objectivity that can capture the essence of reality [2]. Unlike the Soviet school that emphasized montage or the avant-garde directors that focused on formal experimentation, Bazin promoted the shooting methods of long shots and depth of field that emphasized the depth of reality, arguing that this could better present the authenticity and complexity of the world, thus reserving more room for interpretation for the audience. Bazin's theory of realism does not simply require that the film adopt a documentary approach, but hopes that through minimal editing intervention, the audience can fully feel the ‘real existence’ of the characters and scenes. He particularly stressed that the narrative function of a film should strike a balance between reproduction and representation; that is, under the premise of preserving realistic details, the artistic creativity of the director should also be allowed to penetrate into it, so that the audience can obtain spontaneous emotional and cognitive experiences in the world constructed by the film.

The idea of film as an important source of historical research is not new. Marc Ferro, in his book Cinema and History (1988), highlights that film is not only a tool for entertainment, but also an important window for reflecting social ideology and cultural trends [3]. Cinema is usually premised on the aesthetic interests, ideological stance and industrial conditions of its time, and through the language of narrative and images, collective identity is consolidated. Therefore, when retracing the film works of a specific historical period, it can be observed that the social values, and aesthetic standards, as well as, the political and cultural atmosphere of that time. However, the reproduction of history through the medium of film is often subject to various creative conditions and audience expectations, making it difficult to achieve absolute objectivity. This is precisely what Bazin's dimension of realism tells about historical research: a film's narrative of history and society is both an extension of objective reality and inevitably incorporates the subjective tendencies of the director, screenwriter, and producer. Consequently, to use film as evidence for historical research, it is necessary to take into account multiple factors such as creative motives, industrial systems, and audience responses in textual analyses.

3. Casablanca (1942)

3.1. Filmography

Casablanca was released in 1942, and the United States officially entered the war after Pearl Harbor at the end of 1941, when the entire European theatre was still fiercely engaged. The film's choice of a non-direct battlefield - Casablanca, Morocco - as the setting for the story weaves together the turmoil of the times with romantic love, creating a unique narrative tension. The film's protagonist, Rick Blaine (played by Humphrey Bogart), is originally a politically apathetic bar owner, but in the second half of the film, out of patriotism and a sense of duty to fight against the Nazis, he takes the initiative to help Victor Laszlo, a leader of the Resistance, escape from danger, thus completing the character's transformation from apathy to passion.

During World War II, the United States did not enter the war directly from the beginning, but due to the political climate and the tightening of the war in Europe, Hollywood gradually took on the social responsibility of fuelling the war effort. Many films began to incorporate the theme of patriotism or rendering an anti-fascist justice atmosphere, in order to inspire the public's attention and support for the war, these types of films are often external forms of various, but can not avoid the strong political and ideological atmosphere at that time [4]. In American society at that time, promoting patriotism and inspiring people's hearts was an important implicit task of the film industry [5]. Casablanca was launched in this context, and under the narrative framework of romantic love, it contains a distinctive theme of the times, which strongly resonates with the audience on an emotional level. Although the film focuses on romantic relationships, it is difficult for the audience to ignore the multiple connections between the people in the film and the general environment of the times. For example, Rick's feelings for Ilsa are intertwined with his choices for his country and morality; at the end of the film, Rick resolutely decides to let Ilsa go and continue to fight with Laszlo, which is a romantic and sad ending of love, and also a declaration of loyalty to the country and the world's just cause.

3.2. Theoretical Analysis

Starting from Bazin's realism, although Casablanca is not a strict documentary film, it still reflects the historical environment and social psychology of the time through many narrative details and characterization [4]. Director Michael Curtiz, in dealing with the relationship between the characters, uses a more realistic scene dispatch to show the complex interpersonal relationship of Casablanca as a place of refuge: refugees fleeing from the war, intelligence traffickers, Nazi forces, officials of the French Vichy government and other roles in turn, to create a real and legendary microcosm of the immigrant city. At the same time, the film also assumed a social function, which played an active role in inspiring American audiences' patriotism and sense of justice against the Nazis [6]. For example, the famous ‘Marseillaise’ duet in the film is regarded as one of the most emotional climaxes of the film in current film history research. Laszlo leads the audience to sing the ‘Marseillaise’ against the Nazis, which demonstrates the spirit of resistance and injects the audience with a moral and emotional resonance. At this point, the audience felt the emotions of the characters, which resonated with the mainstream values of society at that time (anti-Nazi and pro-freedom). This echoing of the needs of the current era reflects what Bazin calls the close-to-reality nature of the film. As the War has passed, historians and critics have come to regard Casablanca as a valuable source of information about the mentality of American society during World War II. The film came out before the war was over, and as a result, its narrative and the fate of its characters have a sense of ongoing urgency rather than a post-war hindsight review of that period of history. It is this timeliness that makes Casablanca both a romantic love story and an important reflection of the international situation and public psyche of the time. Audiences today can look back on the film and see through the choices and values of its characters the collective imagination and aspirations of American society for freedom and morality during World War II.

4. Singin' in the Rain (1952)

4.1. Filmography

Released in 1952, Singin' in the Rain is widely regarded as a classic Hollywood musical film. Its story is set in the late 1920s - the transition from silent to talkies. The main characters, Don Lockwood (played by Gene Kelly) and Lina Lamont (played by Jean Hagen), were originally the popular on-screen couple of the silent film, but with the advent of sound technology, Lina's noisy voice contrasts sharply with Don's versatility. The film is an intriguing drama that chronicles an epochal technological innovation in the film industry.

Although the narrative focuses on the late 1920s, the film itself was born in the 1950s, an era when Hollywood was facing a huge onslaught from television. The Studio System was facing a decline, and the studios had to find a new attraction. Musical films were rich in audio-visual elements that lent themselves to showcasing the colours, music and dance of the big screen, satisfying the audience's need for entertainment and visual spectacle. Singin' in the Rain is in this sense both a work of nostalgia, commemorating the golden memories of the transition from silent to sound, and at the same time a clever response to the plight of the film industry at the time.

4.2. Theoretical Analysis

If starting from Bazin's emphasis on realism, the staged performances and intense song and dance scenes of Singin’ in the Rain do not seem to have traditional documentary characteristics. However, Bazin points out that the authenticity of film is not limited to documentary style; the narrative atmosphere created through the elements of scenes, performances, and camera language can also be a reproduction of a specific era and social thinking [7]. The film uses song and dance to render the awkwardness and conflict of the alternation between the silent era and the sound era, outlining the star system, audience tastes, and the sidelights of the studio's commercial operations, providing the audience with an entertaining but historically rich look back. For example, the scenes inside and outside the studio shown several times in the film - the interactions between the director, the producer, the young actors, and the audience on the set - graphically convey the hilarity of the hand-wringing and failed technological experiments in the process of the transition from silent to sound. The audience gets both a comedic viewing experience and a more or less realistic glimpse of Hollywood's industrial transformation from the dilemma of the protagonists. As Bazin said, the poetry of cinema often comes from capturing certain parts of reality authentically [2]. At the same time, Singin’ in the Rain’s remembrance of technological change and satire of the industry's ecology is what gives it a certain value of historical observation.

American society in the 1950s was in a period of post-war prosperity intertwined with the shadow of the Cold War. The popularity of television and the process of suburbanisation made more and more people inclined to consume entertainment at home. Faced with this situation, Hollywood attempted to retain audiences in the cinema with high-budget, widescreen, technicolour, and big-budget productions in the form of musicals. Singin' in the Rain, with its energetic and joyful song and dance performances, satisfies the audience's need for relaxation and happiness outside the high-pressure reality [8]. Therefore, the film is not only a retrospective of the changes in the film industry in the 1920s, but also a projection of the self-positioning of the film industry in the 1950s. By looking back to the classic era, the musical film creates an optimistic and positive viewing experience, full of spectacle and romance, and provides the audience with a moment of spiritual comfort under the shadow of the Cold War and the pressure of reality. Singin' in the Rain, on the one hand, serves the function of self-honour-reviewing the development of Hollywood; on the other hand, it enhances the public's enthusiasm for consumption and cultural identity through the hilarious and joyful song and dance scenes.

5. Comparison and Discussion

Comparing Casablanca and Singin' in the Rain, it can be found that although their genres and themes are obviously different, both of them have more or less assumed the historical reappearance and social functions in specific historical contexts. Casablanca combines love and war, and makes a fervent expression and call for war and patriotism before the film departs from the real process of World War II. While Singin' in the Rain seems to be about the past events of the 1920s, but it examines the history of the industry from the 1950s, and records the technological changes and industrial ecology in the form of songs and dances. Both incorporate echoes of history and society into their narrative structure; one focuses on the reality of resistance, while the other looks back to the evolution of the past.

From the perspective of the creative process, war context films in the 1940s were generally tinged with political propaganda or social mobilisation, and studios were often intent on serving the war effort, either at the urging of the government or consciously by the industry, as exemplified by Casablanca. In the 1950s, on the other hand, the film industry was mainly focused on competing with television, and the key issue was how to survive with a limited audience. The musical film was suitable for entertainment and technological innovation, and thus became an important genre at the time, as evidenced by the creation of Singin' in the Rain. It can be stated that the creative process of both films was deeply influenced by their time and market logic.

By analysing Casablanca and Singin' in the Rain, it can be gained a fuller understanding of how Hollywood in the 1940s-1960s restored the historical and social concerns of its own time on a narrative level, as well as gaining insights into the socio-political, economic, and cultural influences on the process of film-making. Bazin's film theory provides the key theoretical support for this study; his emphasis on realism and the function of reproduction reminds that when analysing the historicity of a film, one should pay attention to the marks of the era presented by the film's narrative and images themselves, and more importantly, not to neglect the social context of the film's creation and dissemination.

6. Conclusion

Casablanca, as a typical romantic war film during World War II, although taking love as the main body in its genre, has made a name for itself in film history for its subtle sense of historical urgency and strong patriotic mobilisation; Singin' in the Rain, on the other hand, from the point of view of technological innovation, has completed the irony and memory of Hollywood's industrial ecology in the form of music. Both of them provide a kind of refraction or metaphor of the real history in their narrative structure, and at the same time, they play the role of rallying the audience's emotion and guiding the public's psychology in those times. Viewed from a contemporary perspective, they are not only classic works of entertainment, but also important documents for understanding the social trends and the development of the American film industry during that period. The splendour and changes created by Hollywood in the middle of the last century demonstrated the maturity of the industrialised film system, and the social mentality, political demands and technological evolution of different periods were deeply imprinted in light and shadow through specific film texts. As Bazin said, cinema is a continuous excavation of reality, and for historical researchers, this kind of excavation will continue to unfold, providing us with new perspectives and methods to understand the world of the past.

Using Bazin's theory of cinematic realism as the main analytical framework, this study explores the reproduction and construction of the social atmosphere of Hollywood films in specific historical situations. However, Bazin's theory itself is biased towards the essential characteristics of the film medium and has limited explanatory power for external factors such as social, political and economic factors, thus it is not yet possible to provide a panoramic understanding of the era in which the film is set. In order to explore the interaction mechanism between film and history and society in greater depth, in addition to further sorting out the interaction between the film industry and national policies and ideologies, more theories of sociology, history and cultural studies should be included in the analysis, to look at the process of film production and dissemination from a multidisciplinary perspective. In addition, only two films, Casablanca and Singin' in the Rain, have been selected as case studies in this study. Although they are typical in terms of genre and theme, the limitations of the sample size and the range of subjects make it difficult to adequately present the diversity of the development of Hollywood in the 1940s-1960s. Future research can try to expand to more genres or a wider time period, both vertically to explore how films at different historical stages reflect and influence social psychology, and horizontally to compare Hollywood's film practices with those of other countries or regions, to reveal more comprehensively the complexity of cinema's reproduction of the historical and social atmosphere in different cultural contexts.