Hi. In the current PS Touch version there is no option where you can change the pixel/inch.
You can workaround this with the following steps…
For example the Retina display of the new iPad has a
2048-by-1536-pixel resolution at 264 pixels per inch (pip).
When you open up a default blank project in PS Touch you will notice that it has 2048x1536 as the document size.
To make it 100 pixel per inch try to divide the width and+height of your document by 2,64.
Hope that answers your question.
Thanks----I will give that a try. Is there another Adobe product which would be better----???? I do not think any of the mega desktop applications have a version for the IPAD.....