Ah think I have it now. The print size on the original image was 12x18. If I resize the print size with resampling unchecked then the dpi increases to over 300 @ 10x8, and higher for smaller prints.

And every one said, 'If we only live,
We too will go to sea in a Sieve,---
To the hills of the Chankly Bore!'
Far and few, far and few, Are the lands where the Jumblies live;
Their heads are green, and their hands are blue, And they went to sea in a Sieve.

Edward Lear
http://www.nonsenselit.org/Lear/ns/jumblies.html