Screen Optimization
| Technology | Screen Optimization (Hinting) | ||
| Description | A post-design process which adds data to a scalable font which is used upon display to adjust its outlines to align better with the pixel grid, ensuring legibility and design integrity across different sizes and resolutions | ||
| Availability | Industry standard | ||
Introduction
Since the commercial availability of scalable fonts in the late 1970s, displaying a typeface accurately, legibly, and readably on a screen has posed significant technical challenges. These difficulties demanded innovative solutions to allow scalable fonts to be optimized for digital displays and other low-resolution devices, and the diverse techniques which emerged to tackle screen optimization (also commonly referred to as ‘hinting’) continue to play a crucial role in the user experience in modern digital typography.
Understanding the Challenge: Pixel Grid and Scalable Fonts
The crux of the problem lies in the discrepancy between the flexibility of scalable fonts and the rigidity of the pixel grid that displays them. Scalable fonts, unlike bitmap fonts, can be resized to any desired scale without losing quality. However, when rendered on a pixel grid, the edges of curves and strokes will often misalign with the rigid pixels. This can lead to distorted, ambiguous, or inconsistent characters, affecting accessibility, readability, and aesthetic appeal.
The Evolution of Hinting
Early hinting technologies allowed a font engineer to add suggestions to an outline as to how it should be treated, marking key features and relationships. It was then up to the rasterizer (the software that converts outlines into bitmaps for screen or print), to interpret those suggestions. This is where the term ‘hinting’ came from – software following suggestions that the engineer had hinted at. However, there was no guarantee of consistency, with different rasterizer implementations often giving wildly different results.
It was not until the introduction of TrueType by Apple in the early 1990s that the situation improved significantly, when ‘hinting’ became ‘instructing’. TrueType incorporates a low-level hinting language which is stored as bytecode next to each glyph in the font file. It allows a skilled engineer to control the precise behaviour of every point on every outline at every size and resolution, with unprecedented features to deliver absolute consistency. As TrueType hinting is precisely defined by the specification, every rasterizer is guaranteed to behave in exactly the same way, giving universal consistency.
OpenType fonts, as a unification of what went before, can contain either PostScript/CFF or TrueType outlines, but can use only the hinting approach which matches the format of its outlines.
More recently, our own technology PixelFix produces TrueType-style hints but makes smart trade-offs to improve clarity without significantly increasing file size, a key consideration in the era of web fonts.
Manual versus Automatic versus PixelFix
Traditional hinting techniques have been broadly classified into two categories: manual and automatic hinting (autohinting).
Manual hinting involves a skilled engineer attaching additional data or code to font outlines, requiring significant time and expertise.
Autohinting is performed by software algorithms that analyse the outlines and add appropriate hints, requiring less human intervention, but producing less pleasing and often much less consistent results.
Dalton Maag’s PixelFix font technology sits somewhere between manual hinting and autohinting. It offers the font engineer much more control than an autohinter, but incorporates only code from a prebuilt library of functions into the font file, making the process much quicker than manual hinting but still delivering a consistent and pleasing result.
The Role of Hinting in User Experience
As our work, home, and leisure lives are dominated by digital displays, the importance of hinting cannot be overstated. Good hinting ensures the legibility and visual appeal of fonts on screens of all types, directly impacting the user experience. It helps maintain consistency in a brand's visual identity across digital platforms, and plays a crucial role in internationalization, ensuring that different languages display consistently and legibly.
Variable Fonts and Hinting
Variable fonts also brought new challenges and opportunities for hinting. It became apparent soon after the introduction of variable fonts in 2016 that getting good results with traditional hinting techniques was both practically difficult and economically challenging. These challenges were our main impetus for developing PixelFix as an alternative, which we introduced in 2020.
The Future of Hinting
As display technologies evolve towards higher pixel densities, the need for hinting might seem less relevant – the death of hinting has been prophesized since the early 2000s – but the increasing diversity in display sizes and resolutions, from smartwatches to large TVs and digital billboards, makes the need for well-hinted fonts as crucial as ever. Put simply, more people expect good-looking, performant fonts in more places than ever before.
Conclusion
Screen optimization (hinting) has played a crucial role in the evolution of digital typography. Despite the effort required, it's an indispensable process that significantly enhances accessibility, aesthetics, and the user experience on digital platforms. As we continue to innovate and push the boundaries of display technologies, the role of hinting in digital typography will remain paramount.