MacFormat UK – June 2019

EDITED BY HOWARD OAKLEY

What’s inside

56

PDF VIEWING

PROBLEMS

Learn why not all PDF

readers are equal

57

iOS SOFTWARE

Swipe away your

touchscreen troubles

58-59

MAC HARDWARE

We solve your

hardware hassles

60-61

MAC SOFTWARE

We resolve restrictions

with your Mac apps

Contact us

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and your questions to
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Why is Portable Document

Format not always portable?

example. Preview and apps that rely on the

Quartz 2D engine cannot render those files

correctly, shown as ‘X’ marks by the engine’s

test suite, which disrupts colour graphics.

Adobe Acrobat, even the free Reader DC

version, makes use of Adobe’s own PDF engine

internally. So with Reader, essentially you get

the same rendering as in its expensive Pro

version, but with limited features beyond that.

Adobe’s engine is compliant with all the major

PDF variants, including the PDF/X family, so

should render documents flawlessly.

Writing a PDF engine to support all these

standards is a fearsome task, and a huge

investment for a small market. Adobe has had

well over 25 years to get it right, and wrote the

predecessors of the current PDF standards.

Q

Why can’t Preview and third-party

apps open some PDF files properly,

but Adobe Acrobat can?

by CLAIRE GEORGE

A

Although PDF is an open standard,

it has a long and complex history.

It encompasses several standards

including PDF/A for archival use, PDF/X for

pre-press, and PDF/UA for accessibility. The

Quartz 2D PDF engine in macOS can read

each variant, but doesn’t cater for their special

features, which are left up to apps to handle.

Problems become most apparent when

a document complies with the PDF/X-4

standard, which is widely used in pre-press,

as it caters for process and spot colour, for

Our resident genius

solves your Mac and

iOS problems

EXPERT

ADVICE

56 | MACFORMAT

View any test of compliance with the

PDF/X-4 standard in Preview and

you’ll see ‘X’ marks where it fails.