Canvas print help

[hector]

Does anyone here have experience of printing photos onto canvas? I want to blow up a pic for a friends birthday present, using one of the many ebay sellers who all have good feedback.

Here is the image, taken with a D40 so it's 6 megapixels, around 3000x2000, click to make it larger (I have actually cloned out the crane since I uploaded it).

http://chthomson.smugmug.com/photos/346503006_Jpjyy-M.jpg (http://chthomson.smugmug.com/photos/346503006_Jpjyy-O.jpg)

What is the largest size you guys would recommend doing? A3? A2? It doesn't have to be pin sharp, just OK to look good on his wall.
Here is a link to the sort of ebay seller I mean (http://cgi.ebay.co.uk/YOUR-PHOTO-ON-TO-AN-A2-SIZE-BOX-FRAMED-CANVAS-24-x20_W0QQitemZ310071463376QQihZ021QQcategoryZ20147QQtcZphotoQQcmdZViewItemQQ_trksidZp1742.m153.l1262) .

Any help would be greatly appreciated!
Thanks

[ChrisA]

Likely some eBay printers are OK. But printing even at a first tier professional lab is not that expensive.

The maximum size depends on your criteria for sharpness and the expected viewing distance. For prints held in the hand many people agree they need to be 300DPI. If mounted on the wall you might get away with 200 DPI if you think people will not be getting closer then 30 or so inches from the print. You will need the full 300 DPI is you want the print to withstand very close inspection.

So, if the image is 3,000 pixels wide and you want to print at 200 DPI you can go up to 3000/200 = 15 inches wide. 150 DPI is the quality found in color magazines and posters. Not quite "photo quality".

[hector]

Thanks alot, sounds like good advice. I think 200DPI should be fine, the picture isn't all that sharp to start off with (the camera was balanced in my shoe on top of a bollard for 30 seconds since I don't have a tripod).
I imagine I will go with a print about 18" x 12", and use one of the ebay guys as I don't really want to spend too much (I realise you probably get what you pay for but it should still be a cool present).
Thanks again

[OreoCookie]

If you want large prints (typically larger than 40x60 cm^2), the pictures are printed with a plotter. Typical resolutions are 1440x720 or 2880x1440. Don't worry too much about megapixels here, the larger the print, the larger the typical viewing distance and so I don't think resolution will be a big problem. Even with a professional 16 MP scan of negatives, for example, you will see pixels if you get close enough.

You may want to use Photoshop or so to increase the pixelcount (by interpolation) and then sharpen the image suitably.