I'm thinking of some of the options:
1. I could cut a square mount to fit inside the aperture, so that it sits flush with the existing mount and covers the paper. I could do a reverse bevel round the edges so that the square mount slides over the bevel of the existing mount.
2. The new mount won’t exactly match either the existing mount or the paper. I could do a mount with a black core to make the mismatch with the paper less obvious, but I don’t suppose a black keyline would show if I do a reverse bevel at the edges.
3. Another option to make the colour mismatch between mounts less obvious - I could use black core and bevel the outer edges to form a V-shape with the bevel of the existing mount.
4. I could use a coloured mount, with or without a black core.
5. How wide would I do the mount - just enough to fill the aperture, or covering as much as possible of the paper leaving just the circular aperture showing.
Is this the best thing to do anyway. Has anyone else got any ideas? The customer can see the problem, knows I can't cut a circular aperture, and I think will be happy with any solution that fills the aperture and holds the photograph in place.
PS. I haven't yet agreed to do the job and I could decline it but I'm up for the challenge
![Confused :?](./images/smilies/icon_confused.gif)