I thought I was developing 4 sheets of Formapan 100, but when I checked them after drying I found that two sheets had nothing on them, for the life of me I cant think what happened. The only film I have now is Formapan and Hp4 in sheet film. I did have some Portra, so it might be that type of film, but I have searched on-line to try and find the code but nothing I have found is the same. Anybody any idea on what this sheet film is/was