Selling prints: how big must a file be?

ColinB147 · 8 May 2009

Hi, not sure if this is the right place for this, feel free to move it.

I am considering placing some photos for sale as prints from my website. What I am unsure about is how large a jpg has to be before it is acceptable as a print, at various sizes. I know that it should be roughly 300 ppi and several of my pics would be fine with this; however, with many of them I have to crop severely to get the best composition, so to reach a large enough file size alot of interpolation would be needed. Can anyone give me guidelines about how much to upsize without reducing quality overmuch?

Thanks in advance

Col

ColinB147 · 10 May 2009

Nobody can help here?? Is the question too vague??? (bump!)

simonkit · 10 May 2009

ColinB147 said:
Nobody can help here?? Is the question too vague??? (bump!)

To be honest it is a bit too vague....it very much depends on the final print size, maybe give a couple of examples? Here's a useful article on print sizes..

http://www.northlight-images.co.uk/article_pages/print_viewing_distance.html

BTW..be careful not to get DPI & PPI confused, just incase here's another link..

http://www.tildefrugal.net/photo/dpi.php

Simon

Chappers · 10 May 2009

How big a print do you want to produce?

Obviously there is a limit to the size of print you can get from a particular file size, but I have had fairly large prints ( 20" x 30") from 8Mb files. However it does depend on how you treat the originals. These were from RAW files and they were not over sharpened in the processing.

Also don't forget to look at your optics. Poor glass on any camera can make a good image unusable.

LeeP · 10 May 2009

Well at 300 ppi (natively) will give you:

3600px x 2400px for a 12" x 8" print as an example.

Basically - width x resolution and height x resolution gives you the JPEG size required.

ColinB147 · 10 May 2009

Thanks all...I'll go away, follow those links, and maybe come back with examples if I'm still unsure.

Cheers

pete.rush · 10 May 2009

Not to get into a print war, but I've manged to have printed a A2 print from a 3000 x 2000 pixel image from photobox and they print their poster sizes at 257dpi. Depends what your camera takes as an image size and what quality of print you want. Of course you can buy software which increases the size of your image to allow you to print very large prints, but these won't be printed at 300dpi.

Canon EOS Digital Rebel XS / 1000D 3888 x 2592
Canon EOS Digital Rebel XSi / 450D 4272 x 2848
Canon EOS Digital Rebel XTi / 400 3888 x 2592
Canon EOS Digital Rebel XT / 350D 3456 x 2304
Canon EOS 300D Digital Rebel 3088 x 2056
Canon EOS 50D 4752 x 3168
Canon EOS 40D 3888 x 2592
Canon EOS 30D 3504 x 2336
Canon EOS 20D 3504 x 2336
Canon EOS 10D 3088 x 2056
Canon EOS 5D 4368 x 2912
Canon EOS 1D Mark III 3888 x 2592
Canon EOS 1D Mark II N 3520 x 2336
Canon EOS 1D Mark II 3520 x 2336
Canon EOS 1DS Mark III 5632 x 3750
Canon EOS 1DS Mark II 4992 x 3328

ColinB147 · 12 May 2009

Brilliant advice, thanks.

Regarding how much upsizing is acceptable, I'll use my own judgement.

Cheers

andrewc · 12 May 2009

Depends on how close you intend to view the pictures from. Smaller prints are likely to be handheld or looked at at close quarters in an album, so keep a high dpi. Larger posters or billboards are viewed from a distance so you can drop the dpi.