upsampling?

Hi,

They are going to print a few of my photos at work. They will be printed at 20x15 inches. My images are 6MP (DRebel).

Question: A setting of about 150dpi makes the longest side about 20in. But the printing lab "prefer" images at 300dpi. How do I upsample my images to 300dpi with good a result?

Also, isn't it true that sharpening should be aplied only AFTER all re-sizing, re-sampling and so forth?

Thanks,

I use Genuine Fractals which seems to work very good. You can try using Bicubic Smoother in PS. I have heard the best way without a special program is to upsize a little at a time.

I don't upsize, I let the print firm do it, since they're professionals they or their software can probably do a better job than I can, and it's definitely easier. I have 30x20" prints that I sent at the cameras native resolution, just with a little sharpening, they look great.

Sharpening is a very complex subject, but you should sharpen as the final step. Scottes will be able to tell you more, or do a search.