Resizing for printing question??

[K.ErickPhotography]

I know there are tons of ways, Im struggling trying to get this right for enlargements. So heres what I do.

Image open in cs4

click on crop tool.
change with width and length to the desired size.(in my case 24x20)
use the crop and drag it over the entire image and press enter
I then go to image. image size. and it reads 24x20
adjust the dpi to 300
select bicubic(best for enlargement)
and hit ok

the readings of pixels after all this was down was 7200x600

How does this sound? Am I doing something wrong? Should I be using the aspect ratio instead? Thanks everybody

BTW if it matters I am shooting out of a 50D

[BCampbell]

So, you're trying to make a 20x24" print at 300ppi?

Which would be 7200x6000 pixels, obviously outside your camera's range.

In my experience, you're better off printing at a lower ppi instead of trying to interpolate up to your target size. You should come in around 3801x3168, which is just over 150dpi. This should actually be acceptable at that size, as long as your image isn't flawed. I'd ask your print service to be sure, but you could always try both methods and see which you like better.

[K.ErickPhotography]

well I assumed that the if 300 dpi couldnt handle 20x24 then the dpi would automatically lower itself

What is the proper way to resize an image. Is there a apect ratio chart that has the ratios for each size of print or is it simple math I could do it my head?? Sorry if I sound dumb

[BCampbell]

Nah this comes up all the time, it's really confusing because usually the people asking for images don't know any better themselves.

If you're printing something yourself, it's always best to ask your print service what they recommend. Now, when you say "resize" I'm not 100% sure what you're referring to, it can be interpreted a couple different ways. But basically, if your print service recommends a specific dpi (technically ppi, but hat's a source of confusion too), all you do is either multiply your target print size by the ppi to get the minimum image dimensions, or divide your current image dimesions by the ppi to find your maximum print size at that resolution.

Most people will recommend 300ppi and that's a good high quality resolution up 8x10 or 11x14. Beyond that you can usually get away with lower resolutions because people are viewing from further away. And modern printers can even do some amazing stuff with resolutions as low as 150ppi. Best to ask your print service.