MAC is legacy and read-only here
MAC (MacPaint) is a 1980s one-bit Macintosh bitmap format. It can usually be opened and converted from, but it's long obsolete, so there's no modern encoder to create new MAC files.
Looking for SFW to MAC? Here's why MAC isn't an output option — and the modern formats to use.
We don't create MAC files — it's a legacy format that's effectively read-only. Here's what to convert to instead.
MAC (MacPaint) is a 1980s one-bit Macintosh bitmap format. It can usually be opened and converted from, but it's long obsolete, so there's no modern encoder to create new MAC files.
For a file that opens everywhere, convert your SFW to PNG, JPG or TIFF instead.
SFW is Seattle FilmWorks' proprietary format from its mail-order film-developing service, which delivered scans in this locked format.
How to open SFW opens with SFW converters and IrfanView; convert to JPG to free the images for normal use.
Full SFW format guideMAC is the MacPaint format from the original 1984 Macintosh, storing simple 1-bit black-and-white images at 576×720 — a piece of computing history.
How to open MAC opens in GraphicConverter and ImageMagick; convert to PNG for modern viewing.
Full MAC format guide