Resizing to specific print sizes...

[e.rose]

How do you go about figuring out how to resize a file so that someone would only be able to get a quality print out of an 8x12 or smaller?

 

[Big Mike]

The basic rule of thumb is 300 pixels per linear inch of print. So 2400 x 3600 would work great for 8x12.

However, someone could probably make a much larger print with a file that size (and have it look good). You can't really stop someone from trying to make larger prints by limited the file size...unless you go really small (like 600x400).

And the real problem is that no matter what you tell people, they will do whatever they want...which may mean taking a 600x400 file and printing it to 8.5 x 11 on cheap plain printer paper. Then they put it up on their fridge (looking terrible) and they tell everyone that YOU took the photo.

 

[e.rose]

You can't really stop someone from trying to make larger prints by limited the file size...unless you go really small (like 600x400).

^^^^^ That's what I wanna know. How I can figure out what the smallest that I can go without compromising the quality of the 8x12 print?

And the real problem is that no matter what you tell people, they will do whatever they want...which may mean taking a 600x400 file and printing it to 8.5 x 11 on cheap plain printer paper. Then they put it up on their fridge (looking terrible) and they tell everyone that YOU took the photo.

I'm aware of all that. I push my clients towards prints and products anyway, but I still need to figure this out.

 

[The_Traveler]

a decent 8 x 10 can be printed at 2000 x 2500 (250. Pixels/inch) and I name the file 8x10max_filename.jpg so that the idea gets across.

 

[KmH]

This is a good reason for not giving customers images on a disc. If they are not happy with the print quality, or try to print a different aspect ratio, they think the photographer screwed up.

A good 8x10 can be printed at 100 ppi, if the print is made from a high quality photo.
The 300 ppi rule of thumb is outdated and remains from the early days of digital imaging when top grade pro cameras had 2 - 5 MP.

The math equations:
Pixels / inches = PPI
PPI x Inches = Pixels
Pixels / PPI = Inches

Another thing you can do is limit the file size by lowering the Quality setting when you save the image file.

Print size limits can be included in the use licensing (print release) documentation for the image.

 

[Robin_Usagani]

You really cant. You can easily print lower res 150 ppi photos on canvas and it does not look bad at all. The rough textured surface helps hiding the quality of the photo.

 

[KmH]

MpixPro

http://youtu.be/UjRH1Pw14lU