To resize or not to resize ? That is the question

Muineach

I know this has probably been looked at before, so add me to the "what camera/lens" brigade (no offense intended)

Well I'm looking at getting some of my pictures printed, (I've an 8mp Canon camera), now at full resolution and 240 dpi it comes out at roughly 8inx12in (3/2 ratio).

Now if I want to print a "poster" at 12x18in or 20x30in either I resize or take the dpi(lower) hit ? am I right ?

8x12in says quality is "Very Good"
20x30in says quality is "Good'

If I resize it in photoshop to 20x30in with 240DPI the pixels increase as you would expect I now get "Very Good" for the 20x30in. (I think I understand DPI)

So here's the questions:

1) Am I better of using photoshop for resizing rather than let the online printer do it ?

2) Regardless of whether I resize should I apply extra sharpening to the printed photo's versus the web ? Using something like Nik Software ? which optimizes for different printers etc.

3) Am I just peeing in the wind with this one ? and should I just stick with 8x12in prints and live out my days not wondering about it ?

If I make no sense, it may be that I saw a fox on top of a shed roof, so things seem a bit surreal at the moment

elven

You and your foxes

Sheer logic is teling me that if you need to upres, your best bet would be to do it yourself and apply sharpening afterwards, then send it to the printer.

ThOnda

I would prefere to do all the work on my own, i.e. to have controll all the time about all steps of the process. Leave the smallest possible amount of work and adjustments for some machines operated by automatic algoryhms.