Getting the Desired Image Dimensions from a PNG Export Using Artboards

[Resilient]

thread226-1639359

I resolved the issue of getting not-as-predicted output dimensions on a PNG export by changing the artboard dimensions and testing until I got the result I wanted.

In my case, I wanted an 1100px x 1100px image but instead got a 4583px x 4583px image from the 1100px x 1100px artboard settings. (Output was via File > Export... > Format: PNG | Use Artboards.) By trial and error, I found that a 264px x 264px artboard yields the 1100px x 1100px output.

Here is a short list of correlations that might help someone else home in on the correct output dimensions:
100px x 100px artboard --> 417px x 417px image
150px x 150px artboard --> 625px x 625px image
200px x 200px artboard --> 833px x 833px image
225px x 225px artboard --> 983px x 938px image
250px x 250px artboard --> 1042px x 1042px image
260px x 260px artboard --> 1083px x 1083px image
264px x 264px artboard --> 1100px x 1100px image
265px x 265px artobard --> 1104px x 1104px image
275px x 275px artboard --> 1146px x 1146px image
1100px x 1100px artboard --> 4583px x 4583px image

(Adobe Illustrator CS5.5 running on Lion on MacBook Pro)

 

[apepp]

...are you not using "file > save for web" dialog?

Andrew
==============

http://www.apepp.info

- Graphic Design and Web Design, Exeter, Devon, UK.
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[apepp]

...png export option will vary depending on the dpi setting, so if your dealing with pixels artboard you need 72dpi setting to maintain artboard size...or use the "file > save for web" dialog...

Andrew
==============

http://www.apepp.info

- Graphic Design and Web Design, Exeter, Devon, UK.
==============

 

[spamjim]

I'm unable to see the problem you observed or the one observed in your referenced thread with my Windows and CS6. Illustrator creates the correct size graphics for me now and it has always done that when I used previous versions on both Mac and Windows.

This could either be a Mac bug, a CS5.x bug or user error.

Most reports of this problem on the internet are user error.

 

[spamjim]

Aha... I was typing and missed Andrew's posts. I had not considered that someone would be saving web graphics without "saving for web".

This is a combination of user error and Illustrator bug.

"File->Export..." does not always honor the artboard sizing. That is a bug. And the user should know to "File->Save for web" anyway so they wouldn't have even bothered with "File->Export..."

 

[Resilient]

The File > Export... method was used because the placed original image was a screenshot (of a wireframe model displayed in a Maya scene viewport) and was smaller than the 1100x1100 output size needed, which meant it would lose resolution (and even more quality) if scaled up to fit the artboard. By choosing the File > Export... method, the image could be scaled down instead. Also, a 300dpi resolution could be chosen for the output image. The idea was that as a thumbnail (for others to get a useful preview of the Maya model) it would retain the detail of the relatively thin lines of the wireframe.

However, a test of the PNG-24 output (Save for Web and Devices...) shows just a slight change in scaling and quality, essentially a negligible difference. So thank you for the additional insight. Much appreciated.

 

[apepp]

...in my experience with 3D rendering it's usually best to render out what you need from the 3D program itself...at the size you need it, be it screen or print diemensions.

...if for print, there is no advantage to resample a 72dpi screenshot to 300dpi. Screenshots in print are left and laid out "as is", even if positioned in a layout at 100% scale.

Andrew
==============

http://www.apepp.info

- Graphic Design and Web Design, Exeter, Devon, UK.
==============

 

[spamjim]

a test of the PNG-24 output (Save for Web and Devices...) shows just a slight change in scaling

There should be absolutely no change in scaling. Your computer is wonky or you have something set up incorrectly.