Your files stay on your Mac.
Convertessa reads SGI RGB files — the native raster format from Silicon Graphics workstations — and writes lossless TIFF files compatible with every major image editor and print workflow. Resolution is preserved exactly. All processing happens on your Mac; nothing is uploaded.
Drag one or more .rgb files onto Convertessa, or point it at a folder to convert the whole batch at once.
Choose TIFF from the output format list. Convertessa will write lossless TIFF with all pixel data intact.
Click Convert. Convertessa processes every file locally on your Mac — no internet connection required.
Images, audio, video, documents, archives and eBooks — all converted natively, right on your Mac.
Pick a format you have — see everything Convertessa can turn it into.
Convert hundreds of files at once with per-type group defaults and individual overrides.
First-class support for HEIC, AVIF and WebP — encode and decode, both ways. Read JPEG XL and a dozen more modern formats too.
Drop files anywhere on the window. Native, instant, and exactly what you’d expect on a Mac.
Dial in compression, resolution and bitrate. Keep originals pristine or shrink for sharing.
Never overwrite a file by accident. Convertessa appends safe suffixes automatically.
Every job is logged locally. Re-run a previous conversion or revisit recent outputs in a click.
Bundle your converted files straight into a single ZIP, TAR or 7z — packaged and ready to share the moment a job finishes.
Right-click any file in Finder and choose Convert. A Quick Action handles it on the spot — no need to open the app first.
Shrink Convertessa to a tidy mini window that tucks into a corner — just a drop zone and a format picker for quick, one-off conversions.
No cloud. No account. No upload. Every conversion happens entirely on-device, using the power already in your Mac. What you convert is nobody’s business but yours.
Script conversions, wire them into your build, or batch a folder from the terminal. The same engine, no GUI required.
Read the full CLI documentation →Shrink Convertessa down to a small, focused window — drop, convert, done, with your recent conversions one click away.
macOS 14+ · Apple Silicon & Intel
New formats, new features, and fixes — every release, on the record.
Yes. TIFF is a lossless format and Convertessa preserves every pixel from the source SGI RGB file. No quality is lost in the conversion.
Yes. Convertessa strips embedded metadata from image files, including SGI RGB, during conversion.
Yes. Drag a folder onto Convertessa or pass a folder path to the CLI and every .rgb file inside is converted to TIFF in one pass.