Prints and Image Sizes???

[MrSleepin]

let's say i have an image that is 1920x1200 (it's cropped and sized down)

what's the biggest print size i can go with it?

i am looking at ritzpix.com and the biggest they offer is 24"x36"

could i get the image printed in that size and it would look as sharp as it does on my computer screen? or is it going to get pixelated?

i figured as long as it was bigger than 1920x1080, it should be big enough to not get pixelated... i was thinking about it like i would a tv screen.

 

[KmH]

At 100 PPI it would print 19.2 inches by 12 inches.

1920 px by 1200 px is a different aspect ratio than the 3:2 aspect ratio of an 24" by 36" print.(1920 divided by 1200 = 1.6. 36" divided by 24" = 1.5)

At any rate, to get the 1920 x 1200 pixel image to print in the 24x36 range the PPI will have to be lower than 100.

1920 pixels divided by 36" = 53.33 pixels-per-inch (PPI), which is not very many pixels-per-inch. In fact, ritzpix.com may flag your cropped photo as having insufficient reolution for a 24 x 36 print. Many labs won't risk their reputations on prints made below 100 PPI, which is why I used it in the first line of my post.

1200 px divided by 24" = 50 PPI so, because the aspect ratios don't match the 1920x1200 photo would need to have a tad taken off the long side so it wa also 50 PPI.

Thank god for math because 50 PPI times 36" = 1800 pixels. So to print 36x24 you need a photo that is 1800 x 1200 pixels, if the lab will accept such a small resolution.

The math in summary;

Pixels divided by inches = Pixels-per-inch (PPI)

Pixels divided by PPI = inches

PPI times inches = pixels

 

[MrSleepin]

so no go on the 1920x1200...

i wanna stay around 100ppi
i want the print to be as sharp as possible!


i love your posts! extremely thorough!

 

[Big Mike]

i want the print to be as sharp as possible!

The 'rule of thumb' for photo prints is 300 pixels per linear inch of print. So for a 24" x 36"....you might want 7200 x 10800 pixels (78 megapixels)....which would be a huge file. Thankfully, we don't really need that much resolution for larger prints (which aren't meant to be viewed up close).

Many photographers/printers are OK with 240 pixels per inch, maybe 150 or 100 for larger prints. You can go below 100, but then it's much more likely that you will see pixelization when viewed up close. So keep in mind the viewing distance.
A bill board might be 10 x 30 feet or more...and they probably look terrible from up close, but viewed from afar, they look just fine.

So if your image doesn't have enough pixels from the print size you have, it can be enlarged/extrapolated with software. This will reduce the quality because new pixels will have to be made up, but you may be able to get quite a bit larger before the image really starts to look bad.