Samantha,
One important factor that you didn't mention is how you plan to make the print. Will you use an ink jet printer like the Epson 7600, or will you use a lab to print on traditional paper such as Fuji Crystal Archive?

It's been my experience that, when trying new things, a series of "test strips" is invaluable. I suggest you try a variety of up-resing approaches, then crop a small section of each and make test prints. Be sure to make the prints using the same printer you'll be using for the "final". You should also use test strips to experiment with different amounts of sharpening, and maybe even different image resolutions. Will you resize your image to 360 DPI? How about 300 or 240? Try a variety of sizes and see what you think. Let your eye be the judge of what works best, given the subject and the amount of enlargement you require. If it were me, I'd probably use Genuine Fractals - but it's pretty expensive, and you may be able to do as well using the up-res functions in Photoshop CS.

I don't believe the results will be comparable to prints made from medium format negative film. The 10D is good, but it doesn't have that kind of resolution, IMO.

That said, I would expect a 20x24 print to look pretty good - assuming you don't need to do much cropping.

Good luck - and let us know how this works out.

Enjoy!

-- Jim

To answer your question:

Genuine Fractals is a (somewhat expensive) plugin that some folks recommend.  I used to use it but lost it in a pc upgrade some time ago.  Do a search here, I remember Michael reviewing a couple of other products.

Check out www.fredmiranda.com - he has an action that gives good results by applying the bicubic interpolation in 10% increments.  I use that method, although not his plug in.

Other folks recommend Q-Image which has some different algorithms.  I think you can download a free trial.

In my experience (D30 and 1D) going to 13x19 - other post processing techniques (ie other than how you upsample) can have just as a great an impact - most particularly around sharpening, but also in how you deal with noise - sometimes what appears to be noise free at 8x10 becomes noticable at 13x19.

I don't know what kind of printer you have now - but if it's a good quality photo printer, even if 8x10, I'd do lots of expirementation with crops printed out at 8x10 before I start to think about third party...

One other factor is the quality of your monitor callibration and existing printer profiling - just because you might be happy with the output from your "home" set up is no guarantee you will like what comes out of a commercial operation - again testing their output at a smaller (more economical scale) is mandatory.

Finally, if you know in advance you are shooting for an extreme enlargement, use all the technique you can to get the best shot from the beginning, ie: tripod, RAW, expose to the right, optimum f stop, regardless of the shutter speed, it can't hurt to use MLU & 2 sec delay, etc. etc. ...

good luck

I just photographed a family of 12 with my Canon 10D. They would like a 20 x 24 print made. What software should I use to resize this? Photoshop? Will the quality be comparable to a 645 neg? I have had 11 x 14 prints made from the 10D but nothing this large. Any other advice would be appreciated.

As someone who has had 24 by 30s made from my 10D I have to say yes it can be done with great results.

A few things to consider;

Your work must be good by that I mean good exposure and lighting.  Be it a medium format neg or an digital image a good base makes good results.

Printing;  I really find that for wall portraits (forgive me Epson) that pro labs do the best work for wall portraits in printing on real paper.  The other advantage is that they can mount the print on canvas for a true wall portrait look.  Plus for many labs have big printers that will print out at 150 dpi (printer doubling software or magic) so you won't have to upsize.

Image prep;  Call the lab and find out from them what they require for the file.  Some labs like a final print size while others work a wall portrait this size from a 16 x 20 image size.  Do all the work or maybe the lab will just take the raw file and do it themselves.  Ask about sharpening.  Some labs like it while others do it themselves depending on the final size printed.

If you have any questions just email me.  photoaz@yahoo.com