What each part of the prompt does
- One fixed half
- "The left half stays exactly as it is now" gives the model an anchor, so the comparison is fair. If both halves are allowed to change, the modern side drifts too and the contrast is lost.
- The era as a variable
- [ERA] is the only thing you edit. A decade works better than a vague word like "retro", because each decade comes with a known set of furniture, colours and materials.
- Swap object for object
- Asking for period pieces placed where the modern ones are keeps the layout the same: the sofa becomes a sofa from that time, the lamp becomes an old lamp. That one-to-one swap is what makes the split readable at a glance.
- A seam that lines up
- Walls, windows, doors and the ceiling line continuing across the middle is the detail that sells it as one room. Ruling out a border or label keeps the split clean for you to caption yourself.
Variations to try
Same idea, one thing changed. These have no example image yet.
1970s on the right Split my uploaded room photo straight down the middle. The left half stays exactly as it is now. The right half shows the same room, from the same camera position, as it would have looked in the 1970s: period furniture, wallpaper or paint, flooring, lamps and small objects from that time, placed where the modern ones are. Walls, windows, doors and the ceiling line continue across the split so it reads as one room. A clean vertical seam in the centre, no border or text. Same framing as the original.
1920s on the right Split my uploaded room photo straight down the middle. The left half stays exactly as it is now. The right half shows the same room, from the same camera position, as it would have looked in the 1920s: period furniture, wallpaper or paint, flooring, lamps and small objects from that time, placed where the modern ones are. Walls, windows, doors and the ceiling line continue across the split so it reads as one room. A clean vertical seam in the centre, no border or text. Same framing as the original.
Far future on the right Split my uploaded room photo straight down the middle. The left half stays exactly as it is now. The right half shows the same room, from the same camera position, as it would have looked in the year 2080, imagined as calm and minimal: period furniture, wallpaper or paint, flooring, lamps and small objects from that time, placed where the modern ones are. Walls, windows, doors and the ceiling line continue across the split so it reads as one room. A clean vertical seam in the centre, no border or text. Same framing as the original.
If the result isn't right
- If the left half changes too, reply "leave the left half pixel for pixel as in my photo".
- When the halves do not line up, add "the window frame and the floor line meet exactly at the centre seam".
- Very cluttered rooms can turn into a muddle; clear the main surfaces before you take the photo.
- For a top and bottom split on a tall photo, change "down the middle" to "across the middle" and "left and right" to "top and bottom".