Saving high-quality PDFs at 120dpi

[tatum_ellise]

Hi, I'm creating an exhibition stand and I've been asked to supply the artwork as a high-quality PDF at 120dpi... how do I do this?

Thanks!

[BobLevine]

PDFs do not have resolution. Go back to whoever told you this and get clarification on whether they just mean the images that are used in the document. 

[James Gifford—NitroPress]

I can hazard a guess here. Many designers are not familar with doing work for large format output, and while the vector elements of PDF are resolution-independent, it's common for them to include images that are far, far below a useful effective PPI.

It's a case of having to calculate backward from the actual print size of the image (which can be several feet across) and making sure the document image and the PDF export allows for at least 120 (sometimes 150) pixels per print inch. This means a two-foot-wide print image would have to have/export at some 2800 pixels across.

But yeah, even large format bureaus experienced with inexperience can give pretty garbled instructions. 🙂

[innovative_adventurer5D56]

If they mean PDF for print, difinitly they mean high quality print with this compression specification.

[James Gifford—NitroPress]

Yes, but it's complicated in that large format work is often done in scaled form, so the export values get tricky. If you're working at one inch per foot, or one pica per inch, the PDF will handle all scaling issues EXCEPT for raster images, which must be/export at the full pixel dimesions to achieve 120DPI/LPI at print scale.

[innovative_adventurer5D56]

Eve for Interactive PDF, you can spicify its compression for images and res. 

[rob day]

Hi @tatum_ellise , The printer is asking that any images in your document have an Effective Resolution of at least 120ppi. If there are images placed in your InDesign Document check the Link Info panel, which will list the Effective Resolution (the scaled output resolution) and make sure the Effective Resolution is over 120ppi. 

Also if the PDF is going to be scaled up at output, you would have to consider the print scaling—if the PDF will be printed at 200% the Effective image resolutions would have to be 240ppi in order to gt the 120ppi output resolution.

[Test Screen Name]

I think the key question is what app you intend to use to design the stand. What is that? Or haven't you started yet?

[James Gifford—NitroPress]

I'm not sure that's relevant. Most trade show or exhibition stands simply have places for foam board, flexible board or vinyl fabric art, usually of very large scale. From InDesign to PDF to the large format printer, it's all pretty much the same.

[Brad @ Roaring Mouse]

Displays don't need much in the way of resolution, hence the relatively "low" resolution of 120 ppi asked for. (frankly you'd get by with even half that... noone is going to be that close). And yes, they are only concerned about the resolution of any placed images... they are NOT asking you to render the text or other vector objects to an image of that rsolution. True, if the printer just said "make sure it's 120 ppi, that's a bit lazy speak, but really, most of us know what that means). In a way they are helping out since one doesn't have to worry about placing an uber-high resolution image to get the usual 300 ppi for a 36" wide display... that would just make a humongous file for no reason. That being said, NO PRINTER IS GOING TO COMPLAIN about having too high a resolution in the file.

But they will complain if it's LESS, so the comments about making sure you have a goodly amount of Effective PPI is worth looking into and correcting.

As far as how to export, just change your settings for image resolution on Export.