Dreaming in black and white is read as seeing things in clear opposites, or as looking back at the past. It may also reflect a situation stripped down to its bare essentials.
Where in your waking life have you met something like this lately?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.