Pixels have no size until the PPI is set to reproduce the image.
So my question is this:
If I want to print a 12 x 8 image (3 x 2) what option do I choose?
The aspect ratio of my camera is 3 x 2. I picture compose in the camera so there is usually not a lot cropping to be done. If I ever have to crop, I use the same 3 x 2 aspect ratio.
My camera creates images of 5184 x 3456 (3 x 2).
Do I set the PPI to 432 which produces a 12 x 8 of high resolution
OR
Do I set the PPI at 300 and set the dimensions to 3600 x 2400 to produce a 12 x 8?
I'm not an expert either, but I think you should set PPI on 300 and then you have 2 choices: resize your image to fit in 12x8, or send the image (with too many pixels) to the printer and they resize it. In the first option you control the process and you can do some resharpening after resizing, in the second option you'll have to wait and see the result once the printer has finished the job.
Waaaay back when, when pixels were known (I think) as just coordinates, x and y, I had an Apple 2+ which - no slouch, I upgraded to 64k.
Also the editor of a newsletter called "The Grapevine" which, yes, had grapes in the masthead, I made a design, using
my trusty light pen, and addressed pixels one by one.
They only have "size" because your monitor has a resolution and you can adjust the magnification. The same 100x100 pixel image will print as a one-inch square if you set the resolution to 100 ppi (pixels-per-inch) -- each pixel being (at that point) 1/100" square -- or as a ten-inch square if you set the resolution to 10 ppi with pixels 1/10" square ... for that matter you could print it 100" square if you set it to 1 ppi, but it would look pretty ugly unless viewed from across the street ...
Native resolution differs depending on what kind of printer it is. Epson printers are 360 ppi, and (I think) Canon is 300.
AND
Modern printers are at least as good as photoshop at doing the Interpolation.
SO...
Unless you need to downsize it to (for example) save bits in an uploaded file, you'll probably do at least as well by just printing it at the camera resolution without doing any resizing at all.
The file size is almost double at 432 PPI, compared to file size at 300 PPI.
I guess that could be a problem in itself.
You see I don't know anything about printers. I do know, however, that they take our beautiful square pixels and convert them into dots. Not only that, but dots with space around them.
The camera resolution equates to 432 PPI for a 12 x 8.
So will this high PPI be accepted by those printers you mentioned?
Yes, that should print just fine. If you're printing it yourself, resize it to the size in inches that you want, without resembling, before you print. Then just print. If you're sending it to a lab, just tell them what size you want.
