Adobe PDF Reduction

Hello,

For printing, I am exporting a poster design from a .psd to a .pdf. I need to email and upload the design to get it to the appropriate people, so I reduced the .pdf with Adobe Acrobat Pro.

Is it safe to use a reduced .pdf for printing a design, or will that compromise the quality?

Thanks!

Also, I have a file that I rasterized all the layers to fix some text handling issues, and it seems like the resulting pdf is unable to be reduced (the file size of the reduced pdf file is the same as the original pdf).

The rule-of-thumb, standard resolution is 300 ppi at the size the file will print for brochures, booklets, catalogs, and that sort of thing. You can reduce the resolution below that down to around 250 ppi without compromising the image, but much depends on the image itself.

In addition, there’s JPEG compression which, if the image is compressed too much, will create noticeable JPEG artifacts in the images.

When you’re reducing the size of your image to email it, it’s very possible that you’re reducing it below the acceptable threshold for printing in both these ways. I can’t be sure without seeing the file, but it’s easily possible.

If it’s too large to email, upload the file(s) to a file-sharing service, such as DropBox, Box, Google Drive, etc. Most of them have free accounts that work just fine. Upload it, follow the instructions, and send the URL to the people you mentioned. Then they can download it.

Doing that throws up quite a few red flags unless you really know what you’re doing.

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Good point. I guess my question was what does it mean when Adobe Acrobat is instructed to “Reduce File Size”? It doesn’t really say. But, it looks like if I go to the ‘Optimize File’ tool, I can set the ppi under ‘Advanced Optimization.’

Can you say more on this? I did that because Photoshop was not rendering the text correctly when I saved the file as a .pdf (type that I rotated to be vertical got scrambled, and some of the text was getting cut off in places).

It could be possible that that was happening because I started the project in Illustrator and the saved it as a .psd to work with imagery in Photoshop. No issues occurred after I rasterized the type.

Also, thanks for your replies!

Acrobat settings can be confusing since they’re a bit technical and the interface isn’t as straightforward as it could be.

Optimizing the PDF is different from Reducing the file size, even though optimizing it does generally reduce the file size. When optimizing the file, Acrobat throws out everything that’s not really needed. When reducing the file size Acrobat does a number of things, like JPEG compression, that squeezes the file size down at the expense of quality.

Rasterizing type in Photoshop is OK sometimes but other times it compromises the quality of the type. For example rasteriing a large color headline isn’t likely to result in any noticeable problems because the headline, when printed, will be composed of halftone dots of, typically, 150 lines per inch (or the rough equivalent of that in digital printing). The same is true of smaller type, like colored body copy text composed of various percentages of the process colors. Like the large headline, the type will be composed of dots or ink drops that blur the edges a bit.

However, you said rastering text, and text is usually considered long blocks of type, like entire sentences and paragraphs. If the text is black (as text usually is), rastering it lowers the resolution of the text down to the resolution of the image. If the image resolution is 300 ppi, the text will also be 300ppi.

However, unrasterized text is composed of vector outlines which will output at the resolution of the printer’s RIP (the output device), which is often 2 or 3 thousand dots per inch. The end result of the rasterized text being a reduction in the black text resolution from 2 or 3 thousand dpi to the 300 ppi resolution of the image and the150 lpi resolution of the halftone screen. In other words, the black text will appear a bit jagged once printed. And if the black text starts out as an RGB file, once converted to CMYK, the text will be composed of all four process colors in a rich black, which will create registration issues that muddy the quality of the text even further…

It’s always best to add text in a layout application made to add text, such as InDesign, Quark XPress, Affinity Publisher, Illustrator, and others. Photoshop just isn’t made to handle text-sized type. Headlines, sometimes, but not text.

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Firstly - just want to back @Just-B and that info is very good and follow it.

Secondly - you’re doing the exact correct thing to export the poster to PDF from PSD. That’s a very good workflow to get the file to the right people.

Thirdly - it depends on what settings you’re using in reducing the PDF.
Or is it just the blanket - reduce pdf size?

Now:
To keep your Vector layers, things like, text layers, vector masks and vector shapes from Photoshop - you need to keep these as live text layers, and do not rasterise them.

By rasterising them you are reducing the text (live text which is Vector) to a pixel (which is raster) - so it’s rasterising the text to the native resolution of the PSD file.

If the native resolution of the PSD file is high enough - the text should be ok - but typically when RIP rasterises text it rasterises it to 2400 - which is a lot higher than the faux-300 that is bandied around.

So what happens when you flatten your Live Text (text layers) and vector shapes/vector masks in Photoshop.

They become raster - and your resulting PDF is the same resolution - so reducing the file size in Acrobat will likely not have any affect.

As it’s already - for example - set to 300.
So you’d need to reduce the overall resolution which would impact the text quality.


So my first port to reduce a PDF size would not to use the Reduce File Size - as I believe this only removes header information from a bloated PDF - or change the PDF setting from different versions.

Adobe have a help page about this
https://helpx.adobe.com/ie/acrobat/using/optimizing-pdfs-acrobat-pro.html

Basically - yes Reduce File Size shouldn’t affect quality of the PDF - as it optimises the PDF and only affects images for resolution, and vectors can be left alone, as there’s nothing to optimise.

But, sometimes, to reduce file size - the embedded font information may be stripped.
Which is probably why you’re seeing wonky text when rotating - perhaps.

Instead - I’d use PDF Optimisation - which is in the link I shared with you.

It’s a bit more complicated - but with some experimentation you can get there easily.

I’d say because the font cannot be embedded in PDF - can you tell us the name of the font - whether it was bought or downloaded for free?

If it’s a free font it’s typically not allowed to embed the fonts in PDFs - which is why the text gets scrambled - or basically Acrobat is substituting the font as there is no embed info and the font cannot be used.

You could/should purchase the font you want to use - or contact the font vendor to see if there is a version you can use.

I wouldn’t have gone this way - if you started in Illustrator - you could link the images rather than working with them directly in Illustrator.

That way - you can edit the image in Photoshop - and update the link in Illustrator.
You can then apply your text (live text/vector text) all your vector info etc can be applied in illustrator along with the photo/raster elements.

And you can save to PDF directly from Illustrator - which would give you the best quality output.

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Who are “the appropriate people”?
If they are printers, they should have an “art upload” link where you don’t have to downsize your file at all. If they don’t have one, that would be weird, but then just do the dropbox et al method B suggested (though as a printer I hate Google drive with a passion and Adobe Cloud whatever is a real PITA)

For anyone else just viewing for content check, does it really matter?

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