Post Processing for enlargements question

Hello,

I'm getting some enlargements done of my macro work to sell. I'll be using Costco to get some large prints (up to 12 x 18 ) and posters (up to 20 x 30). The pictures were taken using a 5D so they have a fair amount of resolution. My question is, is it better to use Photoshop’s interpolerization algorithms to increase the resolution or to just send in the original.

I'm figuring if I do the enlargement myself, I can control the sharpness and control the aliasing, sharpness and halos. However I don't have any adaptive algorithm programs like Photozoom or Genuine Fractals, so I don't know if Costco could do a better job then me. Does anyone have any advice or recommendations?

Also, the minimum resolution requirements Costco gives are kind of low:
4x6 _______________690x460 pixels
5x7 _______________805x575 pixels
8x10 ______________1150x920 pixels
8x12 ______________1380x920 pixels
11x14 enlargements __1610x1265 pixels
12x18 enlargements __2070x1380 pixels
16x20 posters _______2300x1840 pixels
20x30 posters _______3450x2300 pixels

Would enlarging the photos that meet or exceed these requirements help the quality of the picture? (I know that enlarging doesn’t add information, but done well it can make the appearance of added information)

Any advice or recommendations would be welcomed.

Thanks,
Robert

I would do the resizing my self , I print my own but if I were to send them out I would still want full control of any PP ,,, Geniune Fractals is very good , but you can also get great results using PS , simple rule in PS when upsizing use Bicubic Smoother , when downsizing use Bicubic Sharper , and if you are going up more than 50% do it in a couple off steps , then do final Proof color and fine tune sharpness and its reay for print .

Rod

Thanks for the advice. For poster prints, what resolution should I be aiming for in the enlargement, or is it better to keep the pixels per inch constant for the enlargement?

Bob , I use 300 dpi up to 16x20 then I go 240 , for big 30x20 posters if its a good shot then 200dpi will be ok as you are standing further away from the big posters ,, its about workflow really and off course the more res the better but the the file gets huge so you balance how your set up can handle big files , Ive had some digital paintings for posters hit 800mg or more after some PP and many layers .

Rod

I agree with Rod. If you have PSCS2 you can do excellent upsizes using this techique:
http://www.outbackphot​o.com/workflow/wf_60/e​ssay.html