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View Full Version : Archival Image Quality of 3f vs. TIFF



b.cipolla
24-Jul-2012, 07:47
Hello all. I'm preparing to scan a very large batch of negatives using a Hasselblad Flextight scanner. I've used the machine before, but I am new to the 3f raw file format that is included with the FlexColor software. I'm aware of the advantages of scanning to 3f in terms of being able to go back and reprocess negatives without having to rescan, but I was wondering if there was any advantage in using 3f over TIFF in terms of archival image quality. Right now, I'm scanning to 16-bit TIFF and then making making adjustments to my images in Camera Raw, and saving as DNG's so that my adjustments are saved. Is this not as safe as scanning to 3f, making adjustments in FlexColor or Photoshop, and then exporting 16-bit TIFF's? My main concern is to maintain and archival image quality and capturing the most available data within the negative. It's my understanding that a 3f file is only a TIFF with extra data added on that enables you to adjust it in FlexColor. Any insight would be appreciated. Thanks!

b.cipolla
24-Jul-2012, 07:53
I forgot to mention that when I scan in TIFF, I am turning all histogram, curves, and flextight settings off, so that there is no clipping. I am using some sharpening by leaving the setting at 0.

Kirk Gittings
24-Jul-2012, 08:21
3f files are not really raw. They never developed the file format. Its a myth. They are just tiffs. You can simply change the extension on a 3f file to .tiff and they work fine as tiffs. If they were a raw format you could not do this. I fell for this for a couple of years before a professional scanner and Jeff Schewe told me the truth. Once you get the scan there is absolutely no advantage to doing additional adjustments back in Flexcolor-you are better off going to PS or Lightroom.

Jim Andrada
24-Jul-2012, 22:55
Also not quite sure what you meant by "archival image quality" in this context. TIFF compression is lossless so you don't lose any quality by compressing (unlike JPEG or many video codecs.)

Of course keeping anything digital truly archived is an enormous can of worms. It can be a fun discussion though.

(Disclosure - my real job relates to development and manufacturing of systems for tape and disk backup and archiving)

Noah A
24-Jul-2012, 23:27
I occasionally use Hasselbad scanners and I've wondered about this too. I don't want to speak for the OP, but I've wondered if 3f will be as readable in the future as TIFF. Of course the TIFF format could become obsolete, but it's much more common than the 3f format so I figure the chances are decent that we'll be able to open TIFF files for quite some time.

I knew 3f files will open in photoshop with a plugin, I often just open them, invert them and process them in PS instead of flexcolor. But I didn't know that they are basically TIFF files, that is very interesting. I never tried changing the extension.

Whenever I scan I tend to save a 'raw' scan, and by this I don't mean a raw digital file, just a scan that's maybe a tiny bit flat with no clipping and no processing after the scan. I then spot it, make my adjustments and save that as a second, working file.

So Kirk (and others), do you save files as 3f for your archive? Or do you just change the extension to TIFF and save that? Or do you open it in PS and save it as a TIFF?

Kirk Gittings
25-Jul-2012, 08:18
I just changed it after saving the scan. That way you don't need the plugin. I haven't used an Imacon in a couple of years. I use an IQSmart now. I think all this is still true.

Leigh
25-Jul-2012, 09:35
I don't understand the question.

Data is data. It has no "archival" quality, nor does it have a definable "life". It exists, period.

The storage medium on which you put it may have a finite lifetime, but the data itself does not.

- Leigh

Kirk Gittings
25-Jul-2012, 09:56
Saving a Tiff as a DNG through ACR is not the same thing as saving a raw file as a DNG. You have no raw data to save from a tiff a tiff is rendered raw info.

Leigh
25-Jul-2012, 10:44
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

Kirk Gittings
25-Jul-2012, 10:56
Leigh I was referring to this statement "I'm scanning to 16-bit TIFF and then making making adjustments to my images in Camera Raw, and saving as DNG's so that my adjustments are saved." There is no way to output a raw file from Flexcolor and a 3f file is really just a tiff. I think that his approach is odd-not wrong. If I were him I would simply open up the 3fs as Tiffs in PS, do my adjustments with adjustment layers and archive that.

Leigh
25-Jul-2012, 10:59
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
25-Jul-2012, 23:23
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
26-Jul-2012, 03:38
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
26-Jul-2012, 08:30
Anything proprietary is not considered archival, if you want archival use unmodified Tiff.

Dominik

Kirk Gittings
26-Jul-2012, 09:46
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
26-Jul-2012, 10:26
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
26-Jul-2012, 10:49
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
26-Jul-2012, 11:09
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
26-Jul-2012, 11:39
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/developer/en/tiff/TIFF6.pdf

MisterPrinter
29-Jul-2012, 14:52
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.

Leigh
29-Jul-2012, 15:04
The TIFF file format is defined as a series of "packets", each identified by a "tag".

Some tags are "vendor defined", meaning those packets can contain whatever data the vendor chooses.

If the TIFF interpreter encounters a packet with an unknown tag, it simply skips that packet,
regardless of its contents, and goes on to the next packet. (see note)

What happens when you choose to open a camera-specific raw file with a TIFF interpreter
is that all of the camera-specific data is simply thrown away.

That does not mean that it doesn't exist. The interpreter just does not know what to do with it, so it's discarded.
This is what the Photoshop error message means.

- Leigh

Note: This is a requirement of any file format that will evolve over time, so it will tolerate and ignore features that are defined in later releases.