I have a technical question for any commercial printers, or someone who has genuine first-hand knowledge of the printing process.
Firstly, let me say that this question is exclusively aimed at dpi and printing, and NOT aimed at ppi and screen display.
Ok, so my question is - when you create a new image file, and initially set the dpi to 300, what does this dpi setting actually do to the file? Does it set some kind of hidden meta-tag, and if so what could that meta-tag possibly do that would benefit the quality???
The reason I am asking is that in theory, the dpi setting should be TOTALLY irrelevant, providing that the image is created at the correct size. Let me give an example.
Suppose I wanted an image printed out at 5 inches by 5 inches. If the commercial printer has told me that they need a 300 dpi image file, then in theory, as long as I create my image at 1500 by 1500, the image should print out at that size. (1500 divided by 300 = 5). If I created the image with smaller dimensions, say 750 by 750, then it would obviously end up 2.5 inches by 2.5 inches (750 divided by 300 =2.5).
Therefore I would like to know the technical process of what the dpi setting does to the actual file itself, and what possible benefit it could offer.
The only reason I can see to use the dpi setting, is if you do not enter pixel dimensions when initially creating the file, and instead set the inch settings. That way you would obviously need to set the dpi setting, in order for the image editing application to multiply the inches size you set, by the dpi you set, in order for it to work out the required number of pixels to create the canvas at.
Thank you all in advance.