About Films(II):The Structure of Films

Hi guys! It’s scheduled to introduce positive films this week, but before that I would like to replenish some information about the structure of photographic films, and the main difference between negative films and positive films, to make you know better about them.

         Both positive and negative films are composed of three layers of light sensing gelatin (乳膠), which sense the color blue, green, red respectively. Between first and second sensitive layer of is yellow color filter layer, which absorbs all the blue light after getting through the sensitive layer. Thus, there were only green light and red light passing the filter layer. With the same principle, the other two sensitive layers absorb different lights and then the light are absorbed by the filter layer.

     

      There are also developer in light sensing latex, which will be the complementary color when the film is processed. This kind of film is called “negative film”. As for positive film, it needs reversal development (反轉顯影) to become the same color of the scenery.

    

       Hope you can have a better understanding of photographic film’s structure. The picture I’d like to share with you today is a Japanese man and a shrine. This was also taken in Japan, after the man had worship a deity. The man’s back gave tranquil atmosphere to the photo, and I couldn’t help thinking he must be a good-looking gentleman!