The color is sensitizing dye. It's normal, and usually washed out by usual chemical process, from developer to final wash.(posted 8439 days ago)The main cause of streaking is not the dry film and developer interaction. It is often said that today's films have reagents in emulsion so that the interaction between dry film surface and developer starts up uniformly. Presoak is therefore said to be not beneficial, and manufacturers tend not to recommend it. It is also often said that developing time needs adjustment when film is presoaked. However, I have not seen any convincing data that support these statements, although I have no reason to disbelieve these statements. I do not presoak.
Anyone measured exposure-density curve at a fixed developing time with and without presoak?