I know there are 'similar' questions on Stack Exchange and the internet, but none has answered my question. I am not confused between Pixels Per Inch (PPI) of the digital image and Dots Per Inch (DPI) printing quality of the printer.
What I am confused about is, all the explanations for determining print size, says to take the numerical value of the largest side of the digital image in PIXELS, then divide it by the numerical value of the largest size of the physical real world print you want to create. This basically says 1 pixel = 1 dot. From memory, one tutorial even said that 1 pixel = 1 dot. I do not believe this is true at all (please correct me if I am wrong). A pixel is the smallest part of a digital image, while a dot is a dot on a print medium, such as sheet of paper or canvas and is determined by a printer. They are not the same (as far as I know) and I thought, and have read, that you should not use DPI to refer to digital images (see this post PPI Doesn’t Matter (and stop saying DPI))
It makes sense that digital images are in PPI, they are after all made of pixels But why are some digital images specified in DPI too? And why do printing businesses still ask for images to be supplied as 300 DPI? DPI as I said, is used to specify printer quality, not digital images. And like this post says, I don't believe dot = pixel. Calculating dots per pixel when printing an image It says: "The article is massively over simplifying things though as that's generally not how printing works. A printed dot does not align with the pixels in an image."
Where in this process does a pixel suddenly equate exactly to one dot, or, more importantly, how can I accurately determine print size? (please do not tell me to divide the largest dimensions in pixels by the largest dimensions of the physical print I want in inches, for reasons I have already mentioned). I don't understand how there is any sort of ratio between PPI and DPI, it's like asking Americans to manufacture something in inches and the Europeans to manufacture something in centimetres then forcing them to be equal somehow, or having a ratio magically appear (like this disaster Mars Probe Lost Due to Simple Math Error). All printers are different, and I was under the impression that a pixel is the same size no matter what kind of printer is used.
Please also add 'conversion', 'pixels', and 'dots' as new tags, and others as necessary. Thank you.