Photojournalists are spotty on history, their history and general history. We know W. Eugene Smith created some great photojournalism. Essential is a funny concept. You get along without something, but it soon becomes essential with use. The same thing applies to history.
History is shown as a horizontal line, leading up to now.
Turn the line to vertical so we can go, up the line to the future, and down to the past. Other histories run parallel. Let's move horizontally - to painting history. The ideal was to make the surface invisible. A painting was a window or a mirror.