This is a sort of guide on canvas sizes, inches, dpi and pixel x pixels.
when it came to canvas sizes, I always kind of assumed that inches belonged with dpi and pixels were just pixels and that everyone knew that; but i read a whole bunch of comments on a tumblr blog where someone asked about canvas sizes, and SO MANY people were replying with things such as, "4000x4000 px at 300 dpi" or "2000x2000 px at 200dpi".
and I guess not everyone quite understands what dpi's really used for xD.
DPI = Dots per Inch. It means how many dots will be printed per inch.
DPI is actually used for printing purposes. It shows the printer how much pixels to print per inch, literally. A common printer (at home or even at a lot of printing stores) at best prints at 150dpi most of the time actually; there are some super duper great printers that can print REALLY fine that can go up to ...apparently a lot more xD; #dpi, so that's why everyone usually suggests saving your project at 300dpi; most printers are fine with 300dpi, because anything above that is a little overkilling it.
There are some super-fine printers though that can print up to maybe 600dpi, but those are not really that common.
alright, so apparently it's pretty common
~ but I've never found myself needing to go above 300dpi; stuff in 150dpi works well for me too, actually >_>;;~ Unless, of course, you're doing extremely high-quality fine-art prints that can sell up to $30-$60 a piece, because really high-quality prints (that requires 600+dpi) costs a lot to print in the first place, so I won't suggest this for anime/comic conventions
so say I have a canvas at 5400 x 3600px, it literally means that I have a canvas that can be printed on a 18 x 12 inch paper at 300 dpi. If I have a 5400 x 3600px canvas at 200dpi, that pixels of the canvas don't change, but the inches on the physical paper can change to 27x18 inches when it comes to printing it. The canvas pixels aren't going to change just because you have it at 200dpi, so putting 200dpi, 300dpi or even 800dpi, it isn't going to make a difference digital canvas-wise. If you say something like "5400 x 3600px at 300 dpi", it's the same as saying "5400 x 3600px at 18 x 12 inches.". See how they don't mix?
Either put down how big it is in pixels (because you don't REALLY need the 300dpi if you're not printing it out), or if you have an intention of printing it out, do it in inches (or cm, if that's what you're used to) with a dpi attached.
Even photoshop makes it clear - The pixels are in the "Pixel-dimention" section, and the inches/cm/mm/etc and dpi is under the "Document-size" section.TL;DR:
Canvas inches and dpis are for physical prints only; Pixels are digital, so they don't mix with dpis or inches, etc. Digital and physical don't mix in a way that would make sense. Please don't say "2000 x 2000px at 300dpi"~ @_@;
I hope I made sense and cleared up some misconceptions about dpi and canvas sizes
.and i hope i didn't make a mistake here hahaha;;;.
sorry if i sounded like a know-it-all v_v;; i guess I found a new pet-peeve D;~
damn, i wrote a lot; sorry, bad habit D:~!
edit: if you're a math-kindda person, you can also look at this mathamatically:
12 x 18inch at 300dpi =
12 x 300 dpi = 3600pixels
18 x 300 = 5400
therefore 12 x 18inch at 300dpi = 3600 x 5400pixels
and that's how you get the pixels vs inches + dpi.