Resolution and Image Dimensions

Hi guys,

I’m interested to know why when I create a document with certain dimensions e.g. 565px by 338px at 150ppi RGB in Illustrator, does the dimensions change to 1614px by 1030px when I export it to PNG with a resolution of 150ppi. Is there a way of saving a high res image (150ppi) while maintaining the original dimensions?

Thanks in advance.

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what program are you using and what settings are you using in the export?

Thanks for your reply. I am using Illustrator and exporting to PNG with a resolution of 150ppi. Apparently, 72ppi for screen viewing gives me some blurring when viewed on a smartphone.

I don’t know why Illustrator outputs PNGs like that. I’ve wondered myself, but never dug far enough into it to figure out since I prefer moving the vector art into Photoshop as a smart object, then sizing it there before flattening.

Hoping you’ll be forgiving if my response crosses into “editorializing” in some way, I’d say the problem is, at least partially, your approach.

You can’t create a document at 150ppi in Illustrator. This is where the flaw takes root. The Illustrator artboard is fundamentally resolution-independent, with the only connection to resolution being the “Document Raster Effects” setting, which, if you don’t apply any raster-based effects, is meaningless.

To be blunt, Illustrator’s raster export stinks. As Illustrator’s primary function is vector graphics creation and output, it simply doesn’t offer enough control over raster output.

It can be an over-simplification, but the way I see it, a workflow has two ends; input and output. When devising the methods that will steer workflow, it is best to consider output first. If raster output is the objective, raster input is most logical. So in that sense, one might ask you, why don’t you just do this work in Photoshop? Of course a totally valid answer would be that the graphics you’re creating are best composed in vectors, since as we all know, many on-screen-destined elements do rightly originate that way.

So how to avoid Illustrator’s pitfall-laced raster export?

Bingo. Your image size/resolution objectives are not an Illustrator strength, so leave that to Photoshop.

  • Set up your canvas of the target size and resolution in Photoshop
  • Design your graphic in Illustrator with no concern whatsoever for size and resolution
  • Copy/paste to Photoshop as a Smart Object, and
  • Enjoy full control over the size and positioning prior to committing it to pixels
  • Benefit from Photoshop’s much wider array of options for PNG output, from Save As at any resolution, to legacy Save for Web, and the newer Quick Export and Export As functions

or save it as a .svg instead of a .png.

Hoo, speaking of pitfalls. [shudder]

That’s where knowing what you are doing and where you are going helps.
I don’t deal with PNGs a lot (other than the folks that think I should print them.) I do deal with some…uh…interesting…SVGs from the TV/Broadcast market. Nothing pitty about them except for the outline view.
That rates a shudder or two if I have to do an extraction.

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