noun
Refers to a standardized format or size, often used for paper, photographs, or other manufactured items.
この写真は規格判ではないので、専用のフレームが必要です。
This photo is not a standard size, so you need a special frame.
判 as a suffix often indicates a size or format (e.g., 四六判, B判). 規格判 is a compound using this suffix.
Compound of 規格 (standard) and 判 (size/format). The exact historical derivation is uncertain, but the word is transparently formed from these components.