When is a 'secondary' source a 'primary source'? This is all a little ambigious!
You have asked an interesting question for in research a secondary source can be a primary source. Let me explain: A lot of original work involves looking freshly at secondary sources. I could, for example offer a major critique of an existing secondary source such as a philosophical text and I would be creating new knowledge.
Thus, definitions of primary and secondary source material are somewhat more fluid than at first glance, and we need to adopt some caution. Let's begin with some definitions:
Generally speaking, primary sources include diaries, speeches, manuscripts, letters, interviews, pamphlets, news film footage, autobiographies/personal narratives, official government records, blog posts, and data for example.
Secondary sources, on the other hand, generally substantiate or build on primary sources and include textbooks, journal and magazine articles, histories, criticisms and commentaries.
However, a secondary source (as described in the definition above) can sometimes become a primary source if the document has been written or created during the time of study. For example, a textbook could be used as primary source material if we are going to use it as evidence of pedagogy for a particular period. Another example which we discussed in class was Jerome Bruner and the relationship of his theories to art education. I gave the example of two of Bruner’s books, The Process of Education (1960) and Towards a Theory of Instruction(1966) which both outline his theories on the circular curriculum. These theories made an impact on the development of curriculum in the 1960s as is evidenced in the MACOS Curriculum Project (held in the Special Collections). Therefore research on the curricula of the 1960s would mean that these two texts would now be considered primary source material, as would the actual curriculum resources generated from the application of Bruner's theories. However, articles about Bruner, his theories and the MACOS project would be considered secondary sources. Thus, as can be seen from these two examples above, primary or secondary designation is almost entirely based on a context and purpose.