AD export persona - *.jpg for press - lack of DPI spettings.

[wintermute]

One issue with jpg export for print purposes. 

I have print specific files - and during export as a jpg there is no dpi setings for jpg. By default file is exported with 150 dpi despite of  fact that document is set at 300 dpi. 

 

Of course there is an option to put exact value in pixels but this is not a comfy solution because you have to calculate dimension in pixel manually…  

[Pšenda]

1 hour ago, wintermute said:

By default file is exported with 150 dpi despite of  fact that document is set at 300 dpi. 

If I understand correctly, you need to export the image at half resolution.

Or do you mean the DPI information written in the file?

Edited January 17 by Pšenda

[wintermute]

19 minutes ago, Pšenda said:

If I understand correctly, you need to export the image at half resolution.

 

No i want to export jpg at 300 dpi, but AD export it at 150 despite of fact that the file resolution is set to 300 dpi. 

1. there is no option to export as 0.5x. If i input this value it change to 1x automatically. 
2. this kind of bug (export with improper dpi) exist in one file. I created another to confirm it but the second file exported is properly.  

 

[PaoloT]

Since JPEG is not the recommended image format for print, wouldn't it be better to replace it with TIFF?

 

[Ldina]

14 minutes ago, PaoloT said:

Since JPEG is not the recommended image format for print, wouldn't it be better to replace it with TIFF?

While TIFF is usually my choice, JPG images work fine for print as long as the quality and resolution are high enough. I've sent hundreds of jobs to press with JPGs.

[Latens]

1 hour ago, wintermute said:

1. there is no option to export as 0.5x. If i input this value it change to 1x automatically. 

Make sure to put in the x after the 0.5

[Pšenda]

22 minutes ago, Circulus said:

Make sure to put in the x after the 0.5

... or the decimal point and comma problem. Although in this case, "2x" is more likely needed.

[Latens]

if I set that field you showed to 300dpi and the scale to 0.5x it wil export at half size but with 300dpi

Isn't that what was asked for?

[fde101]

JPEG files do not store DPI information, so it is meaningless to set one for export to that format.

[MikeW]

1 hour ago, fde101 said:

JPEG files do not store DPI information, so it is meaningless to set one for export to that format.

Really?

[Meliora spero]

1 hour ago, fde101 said:

JPEG files do not store DPI information, so it is meaningless to set one for export to that format.

Fact Check:

• Is DPI supported in JPEG? Yes, DPI information is supported in JPEG files as part of their metadata.
• Where is it stored? In the JFIF or Exif metadata fields, commonly as XResolution and YResolution.
• How long has it been supported? Since JPEG's introduction in 1992, with JFIF and Exif standards supporting DPI metadata.
• Supported in InDesign? Yes, Adobe InDesign recognizes and utilizes DPI information from JPEG files.
• Supported in QuarkXPress? Yes, QuarkXPress also reads and respects DPI metadata in JPEG files.

Fact check time: ~30 seconds.

JFIF (JPEG File Interchange Format) is a specification that defines how JPEG images are stored with metadata, including DPI. It was introduced to ensure proper exchange of JPEG files between systems.

[fde101]

Quote

The JPEG standard does not include any method of coding the resolution or aspect ratio of an image. JFIF provides resolution or aspect ratio information using an application segment extension to JPEG.

https://en.wikipedia.org/wiki/JPEG_File_Interchange_Format

 

The ability to store that resolution data is a commonly but not universally implemented extension to JPEG, not part of JPEG itself.  JPEG images taken directly from digital cameras, for example, do not ordinarily include that metadata.

Regardless, I do stand corrected, as this is evidently implemented commonly enough to be worth including it there.