If you open a large tree (in this case 1610 tips) you will see a complete mess:
![shot1](https://github.com/rambaut/figtree/blob/master/doc/shot1.png)

This is because the default tip label font size is too large. This means that the labels overlap but also take up most of the horizontal screen space, crushing the tree to the left. To fix this, you can shrink the font size (the minimum at the moment is 2pt):
![shot2](https://github.com/rambaut/figtree/blob/master/doc/shot2.png)

So now zoom the tree in the vertical axis only using the 'Expand' slider until the labels aren't overlapping any more. Essentially this creates a very long tree (that you can scroll up and down).
![shot3](https://github.com/rambaut/figtree/blob/master/doc/shot3.png)

Now export as a PDF and you get a PDF of the same aspect ratio:
![shot5](https://github.com/rambaut/figtree/blob/master/doc/shot5.png)

You can zoom in or create a multi-page print out (or a long poster on a continuous roll printer):
![shot4](https://github.com/rambaut/figtree/blob/master/doc/shot4.png)