To understand why you are seeing errors for "F1" or "F2," you first need to understand the technology behind them.

CID stands for Character Identifier. It is a format typically used for large character set fonts, such as those required for Chinese, Japanese, and Korean (CJK) languages. Unlike standard TrueType or OpenType fonts (like Arial or Times New Roman), CID fonts do not have a simple "one-to-one" mapping.

Instead, they use a CIDFont (which contains the glyph outlines) and a CMap (which maps the character codes to the glyphs). This allows for thousands of characters to be stored efficiently.

No legal installer exists. Because F1–F7 are aliases, not real fonts. The real underlying fonts come from different vendors (Adobe, Microsoft, Monotype).

Instead of searching for a risky download, try these verified methods to resolve the font error and view your document correctly.

Google’s Noto Fonts project includes CJK CID-keyed OpenType fonts that perfectly map to F1–F7 when used with Ghostscript.

Verified Download: https://fonts.google.com/noto – search for “CJK.”

After installing Noto fonts, restart your PDF viewer. Adobe Reader will automatically use them as fallback for missing F1–F7.