"Lossless" is a promise. Here's how to check it yourself

"Lossless" gets thrown around a lot. Sometimes it means the picture looks the same, not that the file is the same. A lot of us have been burned by that difference, and it's exactly why so many photographers don't trust anything that promises to shrink their files.

So honestly, I don't want you to trust me either. I want you to check.

What "the same file" really means

There are two very different promises hiding behind "lossless":

• It looks the same. The picture looks identical, but the file is different.
• It IS the same. Every byte of the file matches what your camera wrote.

Only the second one means you still have your original. And the second one you can actually prove, with a fingerprint.

The fingerprint: SHA-256

SHA-256 turns any file into a short string of letters and numbers. Change one byte anywhere in that file and the string changes completely. Same SHA-256, same file. Simple as that.

Windows can do this without installing anything. Open PowerShell and type:

Get-FileHash "C:\Photos\DSC01234.ARW" -Algorithm SHA256

You'll get a long string back. That's your original's fingerprint.

The test

1. Fingerprint your original RAW file and copy the result somewhere.
2. Compress or archive it with whatever tool you're testing.
3. Restore it to a different folder.
4. Fingerprint the restored file.

If the two strings match, you've got your original back. If they don't, you've got something else, no matter what the box says.

This works on any tool. Including mine.

What BatchFox does

When you restore on the default Exact setting, BatchFox Archive gives you your original camera file back byte for byte, and it runs this exact SHA-256 check for you. You can also run it yourself the way I just showed you, no software from me involved.

And getting your photos back is always free. Restore works on every plan, even after the beta. I'm never holding anyone's photos hostage.

BatchFox is in beta. If you want to run this test on your own shoots, sign up at batchfox.app. I'd genuinely love to hear what you find.