A 'simple' colourization of a photo of E. L. Moore's Elizabeth Valley Railroad

Gemini's colourization of an EVRR photo after 4 or 5 prompts

I'm more and more intrigued with the idea of colourizing E. L. Moore's photos of his layouts and dioramas, especially his Elizabeth Valley Railroad. I wanted to do a little test, and decided to ask Gemini to colourize a fairly generic photo of the EVRR. The black-and-white photo below is the one I used:

I'm not going to show the various intermediate steps, but after receiving the initial colourization I asked Gemini to match the colours of the Red Eye Saloon, the Elizabeth Valley station, and the Rocky Ridge depot with the colours they actually were - Gemini had made some guesses.

What it did surprised me: as well as changing the colour on the Elizabeth Valley station and the Rocky Ridge depot Gemini also changed a few details on those buildings. If you look closely you'll see for yourself.

The lesson for me is I'm going to have to create a procedure to retain structural  details across prompts for colour changes. This is something I wasn't expecting, and it makes the colourization exercise somewhat more challenging.