Just found this link which would appear to answer all of the questions about print resolution.

link

This is probably not precisely on topic but some might find it interesting.

The default printing resolution that's usually quoted is 300 dpi, so an 8x10 would be 2400 x 3000 pixels. However, 300 dpi is what used to be requested by publishing houses for magazine reproduction. I always understood, and I haven't tested this, that it is better to have the printing resolution a divisor of the printer resolution. 300 doesn't go into 1440 but 360 does and that is why I've always used 360 when doing prints, with great success over the years.

Thanks very much everyone.

Hi everyone, brand new to PU so just dipping my feet in. I used to use an SP2, ESII and an LX, then on to Canon Digital with L lenses and now solely Pentax K7 and K5 for the past few months. I'll be sticking with Pentax, the advantages are too many to list and well known to everyone here. It's nice to be a Pentax owner again and be able to use a few lenses I used in the 90s on the LX.