Compact PDF refers to reducing the storage space occupied by PDF files by reducing their size. This process includes deleting unnecessary metadata, embedding fonts, image compression and optimization to reduce the file size while maintaining the readability and usability of the document. Slimming PDF is usually to save storage space or improve file transmission efficiency.
Compressing a PDF also includes reducing the size of the PDF file, but it specifically refers to reducing the size of the file by applying a compression algorithm. Common compression algorithms are Flate, JPEG and JBIG2. Lossless or lossy methods can be used for compression. Lossless compression can reduce the file size without losing the image and text quality, while lossy compression may reduce the image and text quality to some extent, but it can achieve higher compression rate.
Therefore, slimming PDF emphasizes reducing file size, while compressing PDF focuses on using compression algorithm to reduce file size. However, in practical application, these two concepts are often confused, and sometimes they can be used as synonyms, depending on the context discussed and the purpose of the operation.