Created a pattern (3600 x 3600 px) which I need to save in JPEG format at 300 dpi. How can I do it without lowering the res?
Shouldn't be a problem at all, so whatever issues you may be experiencing could be technical ones. In any case, without any actual info about your system, your document, your version of AI etc. nobody can really tell you much.
Exporting a 3600px artboard from Illustrator at 300ppi would create a JPEG 15,000 px wide, and I get the same message when attempting it, so perhaps it's outside some hard limit for Illustrator.
If you want to end up with a 300ppi, 3600px JPEG, create it by intended physical size, not pixel size. 3,600 pixels at 300 ppi is 12 inches. So:
1. Create a 12 x 12 in artboard.
2. File > Export As
3. Tick 'Use artboards' in the file browser window.
4. Set to 300 ppi.
Yes, don't EVER choose a size in Illustrator in Pixels if you don't want 72 ppi. It only works for 72 ppi, it doesn't mean what you think. Do the math instead and work out the required size in inches.
Does not look like a limit to me, it works fine in the latest version.
What system ai version do you have and how do you create the jpeg?
You're right, I'm getting variable results now for some reason.
If you're exporting multiple artboards to jpegs, pngs, svg's, etc., when you go to save you need to make sure you have "use artboards" checked and then click all or the range you'd like to export. Otherwise, when "use artboards" isn't checked it thinks you're asking to export the entire workspace and all artboards into one single jpeg.
My fix was to Load the Ai file into photoshop. Had to tweek the size once it was loaded but got the smoother image i wanted.
First u save that file in PDF format then you reopen that pdf in illustrator and save in png format.