Preparing an 20D image for printing?

I have never taken digital images to camera shops for printing. I've shot a portrait of my son which I'd love to have printed tomorrow. I have nearby two normal camera shops which prints digital images to paper and a Leica gallery shop with professional printing equipment available. I'd like to have it printed in all three shops to compare the quality, costs and overall process.

This particular shot is taken with Canon 20D, so size of the image is 2336 x 3504 pixels or 32.444 x 48.667 inches with resolution of 72 ppi when I look at it in Photoshop CS2.

Do I need to resize it for optimal printing results? What about the 72 ppi resolution? I would like to have it printed in several different sizes from small to at least A3 size if not bigger.

Is highest quality JPG OK or should I go for .tiff?

Sorry for such a newbie question, but I've read all the FAQ's here and can't really find a answer to my questions above.

Cheers,
Sterno

Keep the file at its native size, it's big enough for an A3.
Forget about dpi. The actual dpi will determined by the print size. For an A3 it will be nearly 200 ppi.
Highest quality jpg will be fine. The purely theoretical loss in quality will be invisible.

Sterno wrote in post #9460087
I have never taken digital images to camera shops for printing. I've shot a portrait of my son which I'd love to have printed tomorrow. I have nearby two normal camera shops which prints digital images to paper and a Leica gallery shop with professional printing equipment available. I'd like to have it printed in all three shops to compare the quality, costs and overall process.

This particular shot is taken with Canon 20D, so size of the image is 2336 x 3504 pixels or 32.444 x 48.667 inches with resolution of 72 ppi when I look at it in Photoshop CS2.

Do I need to resize it for optimal printing results? What about the 72 ppi resolution? I would like to have it printed in several different sizes from small to at least A3 size if not bigger.

Is highest quality JPG OK or should I go for .tiff?

Sorry for such a newbie question, but I've read all the FAQ's here and can't really find a answer to my questions above.

Cheers,
Sterno

In photoshop go to image size,,, uncheck resample image,,, type in the width and height that you actually want to print,,, now you will see the actual pixels per inch of the print at that size... anything above 200 should look really good,,, 150 even looks good in many cases.

Thanks tzalman and Gseries1! That helps, I think I start to understand now the image size vs. resolution issue.

Cheers,
Sterno

Sterno, to be save you will probably want to convert the image to sRGB in Photoshop, if it's not already in that color space. Some labs will handle other color spaces, others not, so sRGB will probably give you more consistent results.

Cheer tonylong, I checked that they were actually all saved in sRGB.

So I visited all three camera shops today. Two of them had to send the pics to their labs and one of them had a large AGFA printing machine in their store. So I got the prints after 20min wait from there and from the two others shops by the end of the week.

Absolutely amazing looking pics, printed on Kodak Royal paper. Even the cropped images are absolutely crisp sharp in 30cm x 45cm size without any borders.

Very nice surprise and god to know that there isn't too much to worry with getting them printed.

Cheers,
Sterno