First I have used capitals for both History and Film. This is to mark them out as proper nouns. Can we learn or do History in Film? I think the question is far more complicated than it looks and that the conclusion will surprise you.
First I think that Film is an excellent medium for History. I am firmly in the camp that History is an Art and not a Science. Film is an artistic medium so manifesting an art in an artist medium poses fewer problems than presenting an art in a scientific medium. History as Science is like wearing a stiff collar in Church, uncomfortable, unnecessary and for someone else. That being said all art must guard against being a tool of the propagandist. Good art is didactic and welcomes comment and criticism, the propagandist brooks no contradiction.
Second, and I have experience of this, a Historian in a movie theatre must shut up and let other people enjoy the film when non-professionals are present. The problem with film is that the story must take priority over the facts and ‘authenticity’. Film is not History in the same way an essay or a journal article is History where facts and details are important. The story is the most important element and swords, bluebells or rabbits are much less important. Now where that story reflects the historical reality of events we can learn history. A story about the last hours in Hitlers bunker that draws on diaries and interviews can be a useful history compared to a relentlessly authentic medieval survey drama about the Peasants revolt putting modern Marxist thought into the mouths of 14th century peasants. If a film does not accord to the best possible knowledge of the story then we move from history into fantasy and for some narratives, and valuable stories, fantasy is the best medium.
Finally Film is a historical product and one which is part of our inheritance as citizens of a democracy. These are stories we choose to validate by using our time to watch and our money to buy. As active citizens in our democracy we must know where we have come from to understand why the present is as it is and for many film is how we do that. The importance lies in us choosing to watch and spend money on this because it becomes our product and not a propaganda fostered on us by the elite. Such an elite history you can find in museums and art galleries across Britain and see just how attractive they are to the public.
Ultimately all history is for the public and film is probably the most democratic artistic medium available in the current age. The impact of historical film can be seen particularly well in Scotland where the SNP gained a boost from the Braveheart (yes I know.) film and Scottish democracy has been supercharged. The SNP are enjoying the trade wind of popular nationalism not stirring it up which separates them from other nationalist movements. Talking of Braveheart this is an example of a fantasy film with a glancing relationship with history. Its a film which I have never watched but also one that if I did I would be very quiet and let the non-professionals just enjoy it. Do these films have value? Yes I think that they do and if they perpetuate myths, as long as they are benign myths, then I see no problem. If they are malign, the film should be cast out, but myths can be dealt with in articles and journals by professionals. Scientific and professional history needs to stay in the professional realm and let art flourish in the artistic realm and by accepting the opportunities and limitations of film we can create the conditions for valuable history that engages the active citizen to make our world a better place.