PDF blurry in any PDFKit apps, including Preview, Safari, and 3rd party Skim

Question

PDF blurry in any PDFKit apps, including Preview, Safari, and 3rd party Skim

It is time to bring this back again. I am now using High Sierra 10.13.6 (17G65)

If you want to open a PDF with any app using PDFKit provided by the system, especially when you connected to an old monitor, it is non-readable blurry. Check the pics below that I cropped from 1680 x 1050 LCD screen.

Imagery PDF in Preview: (the CaCl2 part is an annotation made in Preview)

Imagery PDF in Acrobat:

Normal text PDF in preview:

Normal text PDF in Acrobat:

I think you all can see the difference. The imagery PDF is unreadable.

I've noticed that there are some complaints about such problems before, but the discussions are all closed by now, and the problem is still there. Also, I don't see any complaints mentioning the even worse situation on a low res display.

I am not dreaming about apple PDFKit to render PDF like an expert. But since PDFKit is widely used across the system, especially in Safari, it is legit to request the files to be at least sharp enough to read.

I know Apple doesn't want to render PDF like windows do, with sub-pixel. But I think the text in Safari is crisp enough and I like the rendering style of that. Why it comes so difficult with PDF? Does Apple not do test for older screens anymore?

Thank you all for reading, if you suffer the same, please leave a note!

MacBook Pro with Retina display, macOS High Sierra (10.13.6)

Posted on Sep 11, 2018 3:02 AM

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Answer 1

dialabrain

Level 10

122,447 points

Sep 11, 2018 4:30 AM in response to ChaofromLeiden

Does Apple not do test for older screens anymore?

You bring up an interesting point. Why would they? It's not like there are many 640x480 or 800x600 monitors sold. And of course there is no way to render text as sharply on them.

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Answer 2

Sep 11, 2018 6:16 AM in response to ChaofromLeiden

As this is a user-to-user support community, none of us have any better insight than you as to what Apple does or does not test, or the physical peripherals involved in that testing.

If you want the best PDF handling and imaging, then use Adobe Acrobat Reader, as only Adobe can remain current with the latest PDF specifications. Preview and Skim are both based on the Apple's PDFKit framework which in turn, is based on PDF v1.3 — an ancient specification.

If you are exporting content to PDF on the Mac from the standard print panel, this is as good as it is going to get. Some third-party applications bring along their own PDF library based on newer PDF specifications, and a custom print panel that accesses that private PDF library. The Affinity (Designer, Photo, Publisher) applications are an example of a private PDF library that generates PDF v1.7 content.

You should consider open-type, sans-serif fonts for detail content such as chemical and mathematical formulas, and I don't mean Arial either. Toggle the Use LCD font smoothing setting in System Preferences -> General panel — and gauge any improvement.

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Answer 3

Sep 11, 2018 8:12 AM in response to VikingOSX

Thank you very much for your reply. It is very detailed and informative. And indeed I am using acrobat softwares for PDF viewing.

But I think you misunderstood the problem. This rendering effect is not due to the different PDF specifications. I have decades old files which show exactly the same result. Also it is not a matter of design. I am not a designer or typographer. It also makes no sense that I read some PDF files I created myself, right?

So, your explanation doesn’t make any sense for me. But hope that will help others.

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Answer 4

Sep 11, 2018 10:31 AM in response to ChaofromLeiden

While I have some issues with pdf display, I see nowhere near as bad a result as your examples present. Of course the display on my iMac 21.5", which has a nonretina display (1920x1080) is nowhere near as nice as on my Retina MBP.

It is clear that Apple does not care much for "nonretina" displays, but I do NOT see the sort of blur as in your first image.

Could you post one or two example pdf where you see this poor result, so we can test?

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Answer 5

Sep 11, 2018 10:27 AM in response to ChaofromLeiden

Check this link for an example file for the first example.

https://www.jianguoyun.com/p/DVEPfvoQscyyBhjM63E

It is a scanned book page, from a 700 page scanned book. This page is extracted using Preview. I've tested this page in both Acrobat reader and Preview, the result is the same as I've shown in my post. I have several of this kind of files to search and read regularly.

I am a researcher, thus reading PDF files from different sources is my daily job. The reason I brought this after using Acrobat for so long is that the rendering speed of this book in Acrobat is really slow, and I got an inconsistent response for moving next and previous pages with either my mouse or keyboard. Then I thought, although it is a bit blurry in Preview, it should be at least readable. At that time I was expecting the effect of my second example. But when I opened the file in Preview, I got angry...

Acrobat reader is always not so responsive compared to other apps. I have a late-2017 MacBook Pro with i7 CPU and 16G ram, plus Radeon Pro 560 graphics card. Thus I think the rendering speed in Acrobat can be worse in lower spec models.

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Answer 6

dialabrain

Level 10

122,447 points

Sep 11, 2018 10:34 AM in response to ChaofromLeiden

ChaofromLeiden wrote:

Please check this file

Example PDF blurry rendering.pdf

Not to put too much into it but there's no info on how it was made or posted etc. Anecdotal evidence is not worth much.

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Answer 7

Sep 11, 2018 11:56 AM in response to dialabrain

That is exactly the same as the origional file. You can open it with Acrobat reader to see the origional look.

It seems to me that you all make PDF files and read the files of your own?

I read PDF files from others, either years ago or new, I don‘t get the chance to decide. Do you?

The point is, it is a clear PDF if not processed by PDFKit. Not only in Acrobat it looks good, even in the Mac Kindle software it looks good too.

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Answer 8

Sep 11, 2018 11:59 AM in response to dialabrain

Sure, I cannot get the info from a 10 year old PDF file. The point is, it can look nicer in Acrobat or even in Kindle.

You don’t read the PDF you made by yourself and control all the fonts and resolution.

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Answer 9

Sep 11, 2018 1:03 PM in response to dialabrain

I don’t understand the point of yours here. I am on a retina screen now and I can not tell clearly which one you used. It seems more likely to be Preview. And probably on a retina or high-res display?

It is large and clear.

But I don’t want to read that file, no matter how clear it shows. I still want to read my book, and mostly on a non-retina display. So you can blame me for not reading a clear book. I accept that. Thanks.

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Answer 10

arshak

Level 1

84 points

Sep 12, 2018 2:31 PM in response to ChaofromLeiden

I am really surprised that this is not a bigger issue. High Sierra is unbearable on my non-retina 2015 21.5" iMac. Sierra, in the latest revisions, came to being acceptable, but things have really deteriorated after Mavericks. Yosemite, El Captain, and early versions of Sierra were terrible in rendering PDFs. The state-of-the-art PDF rendering on Macs was the main reason for me switching in the first place – there was nothing remotely as good as PDFkit, including Adobe software. Now it is the reason I haven't upgraded my MacBook Pro from Mavericks. I don't have hopes for Mojave to improve things: PDF rendering is clearly no longer a priority and most people don't seem to care.

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Answer 11

arshak

Level 1

84 points

Sep 12, 2018 6:35 PM in response to dialabrain

I have done that many times ...

Apple has revised their antialiasing algorithms to optimize for new hardware/ higher resolution displays/ screens and it appears that they use the same algorithm in macOS and iOS. This means that as DPIs on iPhones increase, they will coarsen the antialiasing to look good on the new iPhones, screwing even retina displays on macs in the near future.

Apple's solution: squint your eyes for now and pretend there is no problem and buy a shiny new super-retina mac to read you PDFs as soon as they come out.

My solution: if you care about PDF rendering, roll back to the latest version of Sierra (avoid earlier versions of Sierra). [A more hardcore solution, not for the faint-hearted: roll back all the way to Mavericks]

Another solution is of course to avoid PDFkit altogether, which is also getting easier (PDFs in Chrome, for instance, look relatively good even in High Sierra). Now, if someone could find a good alternative to Skim that supports synctex and doesn't use PDFkit ...

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Answer 12

dialabrain

Level 10

122,447 points

Sep 12, 2018 7:59 PM in response to arshak

arshak wrote:

Apple's solution: squint your eyes for now and pretend there is no problem and buy a shiny new super-retina mac to read you PDFs as soon as they come out.

I haven't read that in any Apple support articles. Since all my Macs have Retina screens but one which is still 2560 x 1440, PDFs look more than acceptable in any PDF reader.

As far as your "solutions", no thanks but you do what you need to do.

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