ตัวแปลงไฟล์ออนไลน์ฟรี G4 เป็น PFM

G4 is a method to compress black and white images without losing quality. It is used for fax machines and as a one of the compression types for the TIFF format. G4 treats a picture as black dots and lines on a white page (less file size will be achieved if there are less black dots and lines).

This is a graphic file format that supports HDR. It is used for exchanging graphics data between applications. It is also used for development in the Netpbm suite of graphics editors. A PBM image has either a per-pixel RGB structure or instructions for representing grayscale tones.