JPG file size differs from the original @ Illustrator

[Rafael Pinheiro BR]

Hi there!

I have created a 4200px x 4800px file @ illustrator. I have done my work and when exporting it to a JPG file the size turns into 17500px x 20000px. Totally insane...

When exporting I have set:

- file > export > export as

- JPG file > marked "use artboards" , then

- RGB mode > quality 10 > resolution 300 dpi

I am using Adobe Illustrator CC 2018 v. 22.1 (the most updated one).

Is there anything I am doing wrong?

Thanks for helping,

Rafael.

[Omar.Fathy]

It is happened because you selected Res 300 ppi when you saved your files so the file size multiplied by 4.1. If your file is 100 px it will be 401 px.
So if you need your file to have it's original size, Use the 72 ppi Resolution when exporting files when you are working with Pixel measurement.

[Rafael Pinheiro BR]

Thank you very much, Omar.Fathy​ ! I also tried this and it worked!

[Jacob Bugge]

Rafael,

The safe way is to use the Save for Web is now hidden away in File>Export>Save for Web (Legacy).

With that you can set the actual pixel x pixel size.

[Danny Whitehead.]

I stuck with 'Save for Web (Legacy)' for a while, but the Asset Export panel and Export For Screens won me over eventually.

Just click on the Artboards tab, and set the format to 1x, and the appropriate compression settings.

[Jacob Bugge]

Thank you, Danny. I will try to remember.

[Test Screen Name]

The crucial thing to know is that you CANNOT size a file in Illustrator in pixels AT ALL. This is confusing because it seems that you can. However, the effect of choosing a document size in "pixels" is exactly the same as choosing it in points - 1/72 inch.

So, imagine you make a document 7200 "pixels" wide. This is actually 100 inches and all talk of pixels is forgotten.

Now, we come to export. The size you export is based on the size in inches and the resolution you export at. By great good luck, if you export at 72 ppi, it's the same. So your 100 inches would export at 7200 pixels. But export at 144 ppi (double), you get 14000 pixels (double). 300 ppi is just over four times the size you might have imagined.

So, export at 72 ppi and fix the resolution outside Illustrator, or design at the needed size in INCHES.

[Danny Whitehead.]

If your artboard is set to either of the mentioned pixel dimensions (the OP's 4200 x 4800, and Test Screen Name's 14000 x 14000), and you Export For Screens at 1x, the pixel dimensions of the export seem to be correct.

The question is, why 300ppi? That's a resolution for print (where resolution actually has real meaning). If you're designing for print, pixels are the wrong unit of measurement. If you're designing for screen, use 72ppi, but it doesn't have any real meaning - only the pixel dimensions matter.

[Not-A-Millennial]

How about exporting a file designed in inches, where the result is a little larger than what you designed?  For instance, I designed something today at 18.0" (w) x 12.0" (h), no bleeds, and the exported file from AI becomes 18.003 x 12.003...and the digital printer I am using rejects the file because it needs an exact 18"x12" JPG file.

Is there a trick you know of I can use? By the way, I am updated to the latest AI.

Thank you for any help.

Bill

[Jacob Bugge]

Non Millennial,

Are your artboard boundaries at whole inch (or point/pixel/pica) values, or slightly off?

[Ton Frederiks]

There is probably a stroke around your artwork that makes it slightly bigger.

[Not-A-Millennial]

Could be, Ton, thanks!

[Ton Frederiks]

If there is a stroke, set the stroke alignement to the inside.

[Rafael Pinheiro BR]

First of all, Omar.Fathy​, Jacob Bugge​, Test Screen Name​ and Danny Whitehead.​ thank you so much for trying to help me!

Danny Whitehead.​ those especifications were sent to me by a client who is designing t-shirts, so after creating the arts in Illustrator they will be printed and sold at his e-commerce.

Jacob Bugge​ thanks a lot! Perfect! Your solution helped me to print it perfectly!

[Jacob Bugge]

For my part you are welcome, Rafael.

[Test Screen Name]

What is your ppi for export? Or do you use pixels per cm?

[Not-A-Millennial]

300x300 dpi  for printing a physical sign.

Bill Simon (personal details removed by moderator).

On Sun, Aug 5, 2018, 4:22 PM Test Screen Name <forums_noreply@adobe.com>

[Jacob Bugge]

Bill,

the digital printer I am using

If it has a PostScript (emulating) driver, what happens if you just print straight from the AI file?

[Not-A-Millennial]

When I said "my digital printer", I meant the actual factory printer. But, I have looked at their acceptable formats, and I see they have expanded from regular JPG to accepting PDF files now, which wouldn't likely risk adding a pixel to the dimensions, so I will re-try with a PDF format.

Appreciate your input!

Bill

[Not-A-Millennial]

The Dots Per Inch are 300x300. This is for printing a physical object.