On Jan 6, 2009, at 12:42 PM, Dan wrote:
>
> At 11:35 AM -0500 1/6/2009, Sam Macomber wrote:
>> On Jan 5, 2009, at 10:20 PM, Dan wrote:
>>> At 5:42 PM -0500 1/5/2009, Sam Macomber wrote:
>>>> From a pro perspective image quality of a TIFF is not good enough,
>>>> RAW is much better.
>>>
>>> Never heard that before. In what way is TIFF lacking?
>>
>> RAW format is all the information captured by the camera's sensor in
>> an unaltered state(though sometimes lossless compression is used,
>> depends on the camera). To generate a TIFF that sensor data has to be
>> altered and when you do so information is lost.
>
> Ok. Been reading up on raw... It's interesting,,, and complicated.
>
> The direct CCD data (raw) is unusable unless you have a profile
> containing the necessary metrics, regarding that particular camera's
> ccd performance. Said profile is sometimes included in the metadata
> buried within the raw file, but not always. IOW, iffa you no gots
> that profile, the raw data is all but useless. My take: Like color
> profiles for printers and displays, this is a nightmare waiting to
> happen. We're going to have to have libraries of thousands of these
> profiles - just to hope to be able to handle a random raw image.
another RAW advantage, it's NOT tagged and manipulated to any one
particular color profile ;)
>
>
> The advantage of the raw data is that it hasn't had its range clipped
> yet; its still up to 14 bits per pixel (jpeg clips to 8 bits after
> gamma correction). That's good - if you can process it correctly.
> Bad - if you cannot process it fully - it leaves you with extra white
> noise.
>
> Most RAW file formats (note the caps now) are "undocumented" (trying
> to not say "proprietary") extensions of TIFF 6.0. (DNG is also an
> extension to TIFF 6.0). ...This is kindof like what people are
> doing to MPEG-4, to create things like DivX and Xvid.
>
> LOL - a gotcha to be aware of - many cameras use a *lossy*
> compression on RAW by default. I'd venture anyone serious about
> wanting RAW needs to turn that off!
>
>
> In four diff places, I've now read comments to the affect that
> because RAW is a non-standard, it is NOT appropriate for long-term /
> archival storage use. They recommend TIFF or JPEG with a lossless or
> zero compression.
>
> I can see why RAW is good for a professional photographer's use in
> the short term. But all the above, taken together, makes me think
> this is a format that's not useful for archival / long-term use. For
> said archive, I guess it can't hurt to keep the RAW file, and the
> profile, as long as you *also* do a TIFF or something.
You explained that much better than i could have. :)
>
>
>>>> At this point with newer systems they're generally all supported by
>>>> Photoshop CameraRAW and can be converted to DNG. i feel that's
>>>> reasonably safe since I'm seeling the useful life right around 10
>>>> years for an image,
>>>
>>> DNG still bothers me a bit. It's an Adobe format, a container for
>>> their particular variant of RAW, based on TIFF.
>>>
>>> I don't trust Adobe much.
>>
>> Part of the reason we have not yet started to convert to DNG, I love
>> the format but you are right all the eggs in one basket.
>
> heh. Just ran across some old PDF files that I cannot seem to open
> anymore. Preview gives an empty window. Adobe Reader crashes.
> Tried full Acrobat on XP - it blue screens. That's a good example of
> how Adobe formats work - even the "open" ones.
oh what fun!
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