What is font subsetting, and why might you use it with custom fonts?

Font subsetting is the process of creating a custom subset of a font file that includes only the glyphs (characters, symbols, and diacritics) required for a specific use case or language support. Rather than including the entire font file with all its glyphs, subsetting allows you to optimize the font file size by including only the necessary characters, thereby reducing bandwidth usage and improving loading times.

Here's why you might use font subsetting with custom fonts:

1. **File Size Optimization**: Font files can contain a vast number of glyphs covering multiple languages, scripts, and symbol sets. Including the entire font file in your web project can result in larger file sizes, which may impact page load times, especially on slower connections or devices. Font subsetting allows you to reduce the file size by including only the glyphs needed for your specific content, thereby optimizing performance.

2. **Bandwidth Reduction**: Smaller font files generated through subsetting require less bandwidth to download, making them more suitable for web environments where data transfer speed and usage are considerations. This can lead to faster loading times and a smoother user experience, particularly on mobile devices or in regions with limited internet connectivity.

3. **Language Support**: If your web project targets specific languages or regions, you can use font subsetting to include only the glyphs necessary for those languages, reducing the font file size while ensuring comprehensive language support. This is particularly useful for multilingual websites where space optimization is essential.

4. **Customization and Tailoring**: Font subsetting allows you to tailor the font file to your specific requirements, including only the characters and symbols relevant to your content. This can be beneficial for projects with limited space or specific design constraints, where optimizing resource usage is a priority.

5. **Compliance and Licensing**: Some font licenses may restrict the redistribution or modification of the font files. Font subsetting allows you to comply with licensing terms by creating custom subsets that include only the permitted glyphs for your use case, ensuring legal compliance while still benefiting from the font's design and functionality.

Overall, font subsetting is a valuable technique for optimizing font file size, reducing bandwidth usage, and tailoring font resources to specific language support or design requirements. By including only the necessary glyphs, you can improve performance, enhance user experience, and ensure legal compliance with font licensing terms.