Importing JPEG into Illustrator - Images not at the actual scale.

[Alan_Silvester]

hi everyone,

I'm trying to import some JPEG images into illustrator to add a very simple vector graphic over the top of some of them. The prolem is that when I import the images the don't appear at the same resolution as they should be. The images are all 600px x 400px 72dpi but when I import them into illustrator the software is readinig them (via the w & h dimensions in my illy browser) as 144px x 96px. Does anyone know why this would be? The odd thing is that when I export them from Illustrator they're showing as 600x400px images again. Is this somethign to do with my import settings or preferences?

Cheers,

Alan

[Monika Gause]

Illustrator reads and interprets the ppi. Are you really sure it's 72 ppi?

[Alan_Silvester]

Hi Monika,

Thanks for your response. I think you're right, they're 300 instead of 72 but why would that be?

[Monika Gause]

Someone must have edited that in an image editor.

[FluentAdobe]

It's easy enough to fix! Right click on the jpg file and choose Properties (Windows) or Get Info (OSX). Look at the dimensions listed, select the jpg in AI and type the dimensions into the Width and Height boxes at the top of your Illustrator toolbar. Constraining the proportions can help to make the process quick and painless. Here's a screen shot of the dialogue:

[Alan_Silvester]

Thanks for this FluentAdobe. It's now displaying the image at its native resolution, without any distortion. Can I ask why Illustrator interpreted the image as smaller than it is? Is this to do with the ppi measurement that Monika is referring to? 

[Steve Fairbairn]

Open the pictures in Photoshop and look at their sizes in centimetres or inches.

Pixels are not units of measure – you can have as many pixels per inch as you like.

[Alan_Silvester]

Ahhh, I get it (I think). Ha, it kind of all makes sense now. So as with an HD resolution you can have that on a 20" or 40" screen but it's only showing the pixel density, rather than the size of image.

But I still don't get why I'm sometimes asked for graphics at a certain pixel size. If I'm tasked with creating graphics at 600px x 400px what measurement should I actually be looking to reference? I'd usually set up my canvas at 600px x 400px and create vextor images at that size but if it's not a size then what size image am I actually creating? I'm aware that vectors are infinatly scalable here but that's not really what I'm asking about.

Sorry if this is confused babble! 

[Monika Gause]

If you're asked for 600 x 400 pixels, create just that. Resolution won't change anything to it.

But in Illustrator, if you export a raster image, don't set resolution to anything else than 72 ppi in the export dialog box or Illustrator will resize your image to different pixel dimensions. There's a couple of threads on that in this forum.

[Alan_Silvester]

OK so on that basis importing images into Illy (for screen) should be set to 72ppi to keep their resolution. So a 600px x 400px image at 72ppi will display as a 600px x 400px image in illustrator and if exported (with grraphics overalyed) at 72ppi will yield a 600px x 400px final image? Right? I'm confused.

[An Elephant]

Go to http://www.wundes.com/JS4AI/ and download "To100Pct". That's what you want.