Adobe Illustrator, dpi, pixels and raster images

Question

I now Ai is all about vectors. So, resolution is not much of an issue, most of the time. Therefore most answers I read about this always consider the vector part but not so much what to do when high resolution raster images are involved.

I need to create, edit and export a document that is 57.15 mm x 88.9 mm. Which is 2.25 inches x 3.5 inches. The print shop template tells me that at 300 dpi, the document size should then be 675px x 1050 px (and higher if dpi's are getting bigger). Fine. A little maths shows that those values match.

The thing is, my illustrations that need to be embedded within the document are set to 800dpi.

If I read the web advises well, all I need is to create a 300 dpi document, go to Menu/effects and change the "Document Raster effect Settings" to 800 dpi. It's 100% the answer to this.

But I don't get it because when I do this, the original document width and height in inches or millimeters doesn't change, but it does shrink in pixels to 162px x 252 px. And that's not good. I need way more than 162px in length and 252 px in width to render a 800dpi picture outputted at 2.25 by 3.5 inches. I just can't understand the maths here.

And if I change the size in pixels as it should (1800px x 2800px) for a document that renders pictures of the right resolution (800dpi), the inches/millimeters will change too. But I need them to be 57.15 mm x 88.9 mm (2.25 inches x 3.5 inches), not bigger.

Based on my understanding, it's the snake biting its own tail. I understand that Ai is vector based but once raster images are involved, it should work as Photoshop does in terms of proportions. But it doesn't. And if it's not an issue, I don't get why.

So I don't now what to do when creating a document. I don't know which values I should prioritize so that my illustrations keep all the details while being rendered at the right physical size: inches/mm, resolution or pixels ?

Understand me well, I'm not questioning the way it works nor am I questioning the answers. I just don't now If I should start with the width and height I want (in inches or millimeters or pixels) but at 300 dpi and change the effect later or if I need to set foresee the final resolution and set a higher width and height (in inches or millimeters or pixels) before I apply th effect. That part is not clear.

So, can someone tell me how to setup my document so that I'm sure I won't have to edit hundreds of files later on to correct my mistakes (which is costly too)?

The thing that is very confusing with Ai is that you can't set an original document to anything higher than 300 dpi. But you can set illustrations to be rastered at 800dpi. But the values remain values of 300 dpi. So you are working at both resolutions at once, but not really. So which one is it? This is anything but intuitive.

Thanks.

Answer 1

In Illustrator set up the new document to the size you want. In your case, that will be 57.15mm x 88.9mm. You don't need to worry about the ppi at this point. Create your artwork, or import your artwork into that new document.

Here are the settings I used for the example below.

When you need to output your work as raster, proceed as follows:

1. Do File > Export As, choose the raster image format desired

2. Select the "Use Artboards" option if you want the image to be the same size as your artboard.

3. Hit Export

4. In the Export dialog set the ppi to your desired value, in your case that's 800ppi

Here's an example. This document was the same size as yours in Illustrator. I pasted some vector images onto the artboard, and I followed the steps above, and finally I checked the image size in Photoshop just to make sure.