Adobe peps up PDF on smartphones with AI-powered Liquid reformatting

The lowly Portable Document Format is a key part of our digital lives, but it "sucks" on small screens.

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Adobe's Acrobat software handles PDF files

Adobe's Acrobat software handles PDF files

Illustration by Stephen Shankland/CNET

Adobe's PDF technology can't match quantum computing's revolutionary potential. But a lot more of the digital world revolves around the lowly Portable Document Format than the newfangled machines, which is why you should take note that Adobe is modernizing it for the smartphone era. 

The company is adding a new AI technology, Liquid mode, to its Acrobat software to reformat files so they're readable on smartphones and other small screens, says Adobe Chief Technology Officer Abhay Parasnis

Liquid mode, announced Wednesday, comes as PDFs play an essential role in our lives, with schools and workplaces moving online, businesses adopting electronic transactions, and people archiving essential documents on thumb drives and cloud storage services.

The technology meets a real need, Adobe says. PDFs are poorly adapted to phones. They don't fit the screens of the smaller devices. Users have to fiddle with the document to read it all.

"It just sucks. You have to pan and zoom," Parasnis said. "All the things that make PDFs great really make PDFs bad on a phone."

How Liquid mode PDFs work

Adobe's Liquid mode liberates the file format from its legacy of a letter-sized page. It uses its knowledge of other documents to predict a layout of text, graphics and tables that'll work on a small phone screen. You'll see the regular PDF view by default when opening a new document, but tapping a button converts it to Liquid mode.

Adobe's Acrobat app gets Liquid mode on Wednesday. The company will offer the technology to other companies, too, so you could see Liquid PDF in browsers, word processors and other tools that handle PDFs.

Adobe created PDF in 1992, but it's no longer proprietary because the company standardized the format through the International Organization for Standardization. And it's big. Trillions of PDF files have been created. Last year, people used Adobe tools to open 250 billion PDFs, the company said. More than 92 million people use Adobe's Acrobat Reader mobile app each month.

Adobe's Liquid mode reformats PDFs so they're more useful on smartphone screens.

Adobe's Liquid mode reformats PDFs so they're more useful on smartphone screens.


One limitation of Liquid mode is that it won't work for text that's just a big graphical element. One example: When you use your phone to take a photo of a document. Adobe plans to beef up Liquid mode with its Scan app's optical character recognition (OCR) technology, which converts those graphics into text, Parasnis said.

Other Adobe ideas for the future of PDFs

Liquid mode and PDF-generation tools from Adobe that launched in July are two aspects of PDF modernization. Adobe has more in mind that will employ Sensei, the brand name it uses for artificial intelligence technology.

One coming upgrade is an ability to summarize a longer PDF by using AI processing to estimate what's most important, Parasnis said. Another is an ability to infer the subject matter of a shorter PDF, then flesh it out with background information retrieved from other sources.

"These documents in effect become interactive, intelligent containers rather than a digital form of an 8 1/2-by-11-inch page," Parasnis said.

Software to process PDFs raises serious concerns -- PDF is in effect a whole programming language -- and AI adds another layer of risk to the technology. AI algorithms can be fooled.

Adobe is guarding against possible abuse, Parasnis said, by working against AI training data biases that can cause problems when the AI system is actually in use. "You have to treat bias in an AI system like security," he said.