With slow fine grain films there is no advantage to adding Sodium Sulfite to Rodinal. If you want a developer which will give similar results with slow films but which can be used well with Sodium Sulfite for fast films, try Edwal FG-7. It is typically used 1:15 with or without Sodium Sulfite so you only need 1/2 ounce for a roll if you use a tank which requires 8 ounces of working solution. FG-7 keeps much longer than Rodinal once it is opened.(posted 8312 days ago)Jeff Adler