Archival Image Quality of 3f vs. TIFF

[Leigh]

If I were him I would simply open up the 3fs as Tiffs in PS, do my adjustments with adjustment layers and archive that.

I agree. That would preserve the original scan, allowing you to go back to that original data if needed.

- Leigh

[neil poulsen]

If you want a raw file, why would you save it in any file format other than the original?

If you can convert it now for archiving, you can just as easily archive the raw file and convert it when you need to work on it.

- Leigh

I think that the question becomes, will there be a converter available for the raw file in a couple of decades. One will always be able to open a TIFF, and I suppose a DNG. But, this might not be true of a raw file.

[Leigh]

Yes, s/w evolution is always a concern. That could argue in favor of saving the TIFF.

But if you have a converter now, that same program will continue to work.

I archive my camera-generated 3F files, modify them in Phocus, then save the results as a TIFF.

- Leigh

[MDR]

Anything proprietary is not considered archival, if you want archival use unmodified Tiff.

Dominik

[Kirk Gittings]

FWIW, one more time. A 3f is not a raw file-it is a tiff (maybe with some Flexcolor adjustments encoded in a side car file). You don't need to "convert" it. You just need to rename the file. Imacons cannot create or save in any true raw format.

[Leigh]

One way to tell whether a file is really just a TIFF is the size.

All TIFF files for a given format and resolution will be exactly the same size, because they're just pixel-by-pixel copies of the data.

If the file sizes differ, there's other information included.

For example, the unmanipulated files from my digital Hasselblad camera carry the extension of 3FR, and are of variable size.
The Phocus s/w will accept these as input and produce either of two output file formats:
One format has an extension of FFF, and is also of variable size.
The other format is a TIF, and is always 117.2MB in size, without exception.

I know the 3FR format uses lossless compression to keep the file size down (in the 40-60MB range).
The FFF files are about 20%-30% larger than the 3FR files. I don't know what the internal format is

Both of these file types are much smaller than the TIFFs, indicating some type of compression is being used.

- Leigh

[Kirk Gittings]

Both of these file types are much smaller than the TIFFs, indicating some type of compression is being used.

Interesting. I never noticed that.

[Mike Anderson]

One way to tell whether a file is really just a TIFF is the size.

All TIFF files for a given format and resolution will be exactly the same size, because they're just pixel-by-pixel copies of the data.

If the file sizes differ, there's other information included.

What? TIFF format supports compression (and other) options.

[Leigh]

What? TIFF format supports compression (and other) options.

Yes, TIFF 6.0 supports Huffman RLL, PackBits, LZW, and JPEG compression algorithms.

However, these may not be compatible with, or readable by, earlier versions of the TIFF decoder.

The TIFFs that I commonly encounter are uncompressed (tag 259=1), which results in fixed-length files.

Other options are possible (tag 259=2).

- Leigh

Ref: TIFF specification, v. 6.0, Sect 3 page 17, downloadable here: http://partners.adobe.com/public/dev...tiff/TIFF6.pdf

[MisterPrinter]

I have re-named both FFF and Creo DT ( Digital Transparency ) files as TIFF files, they open fine in Photoshop but display a warning that some data was unreadable and has been discarded. In the case of the DT files I believe it is a scanner profile for plug-in use, probably the same in the case of FFF.

The DT is "RAW" in the sense that no curves have been applied, it contains everything that the scanner can capture with no clipping, but it's still basically a TIFF.