I recently bought a large second hand poster-size print. It has some slight damage to the sides and a strange stain line across one side (see photos).

I would really like to restore it if possible. I suspect the background was painted with watercolours. I have some experience painting with watercolours and thought maybe I could paint the missing pieces of background as best I could on separate paper and then stick the paper onto the print. (I would try to get the new paper as level with the print as possible but I don't know how I would do that yet.)

Does anyone have any advice on whether this is a good plan?

Or has anyone done something similar and able to share tips that would help?

| [Example of damage on corner](https://i.stack.imgur.com/2nO6p.jpg) | [Example of damage on side](https://i.stack.imgur.com/eeAzi.jpg) | [Example of line on print](https://i.stack.imgur.com/qHpGR.jpg) |
| --- | --- | --- |

Click on images for larger versions