Do any scanners produce "raw" output instead of TIF?

  • Thread starter Thread starter Al Dykes
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A

Al Dykes

It just occurred to me, do any current scanners put out a flavor of
RAW? I prefer RAW when getting files into Photoshop. TIF is more work
for color correction, etc and sometimes my results are not what I
think I could get with RAW.
 
Gridley said:
On 2010-04-13 15:11:31 -0400, Al Dykes said:
Vuescan will output DNG files which are a type of RAW and will open in
Photosop RAW. You can use Vuescan with just about any scanner.
Click to expand...

Moreover, Vuescan will eat its own dogfood - so you can "scan" your RAW files into
Vuescan and apply whatever options you like again in a different manner - such as
dust removal etc.
 
I don't think that the question is relevant. TIFF is an uncompressed
format (ok, there are compressed variants, but as used by scanners, it's
uncompressed). On a digital camera, there is image processing related
to the exposure and focus of the camera. But that is not the case with
a scanner. In some regards, a camera and a scanner are quite different
(for example, in a camera, the entire image lies in a single plane;
there is no depth of the image itself (although the film may not be
completely flat). The point of TIFF is to have the camera do no digital
processing and let it be done in the computer. But the type of such
processing done in a camera is not relevant to a scanner anyway. Also,
scanners don't scan the entire image at once, they scan a single (or
sometimes, a few) lines across the image and move the image, which is
very different from what a camera does. Once you have the RGB values of
each pixel (without any compression, e.g. in uncompressed TIFF format),
that's as "raw" as you can get.
 
Al Dykes said:
It just occurred to me, do any current scanners put out a flavor of
RAW? I prefer RAW when getting files into Photoshop. TIF is more work
for color correction, etc and sometimes my results are not what I
think I could get with RAW.
Click to expand...

Vuescan does output raw scanner data with any scanner if you want it to,
but it is important to know that RAW files from a digital camera and raw
scanner data are two totally different things.

The camera RAW file is a dump of the camera sensors content before
applying the Bayer matrix. So, every pixel has just one colour and the
rest is done by interpolating the remaing two colours within Photoshop
or whatever camera raw converter you're using.

Scanner raw data have RGB values for every pixel and they're just not
colour- or gamma-corrected.

So, you can't simply crank raw scanner data through an engine intended
for treating camera raw data.

You can however use Vuescan to save the raw scanner data (as a TIFF file
with no correction applied) and open this file in Photoshop and manually
apply all the correction Vuescan (or any other scanner software for that
matter) would apply automatically.

I take it Vuescan is even able to save scanner data as a DNG file. I
just don't see any sense in doing so because it would mean applying a
fake a Bayer matrix that would then again be decoded by Photoshop's raw
converter and you'd certainly lose information in this process.

Ralf
 
It just occurred to me, do any current scanners put out a flavor of
RAW?  I prefer RAW when getting files into Photoshop. TIF is more work
for color correction, etc and sometimes my results are not what I
think I could get with  RAW.
Click to expand...

All scanners produce raw images. It's the software that processes
these that outputs either a "raw" file or a processed one.
"raw" scan data is different from digital camera raw data, hence the
two are not exactly comparable. Although there are similarities.
TIF is not your limiting factor, in fact most "raw" files are actually
TIF: it's a file format, not the nature of the data in it.
Vuescan is an example of software that can optionally output a TIF
file containing raw scan data with 16-bit colour depth, which you can
then successfully and extensively post-process in Photoshop.
It will also output in other formats, including 8-bit TIF and 8-bit
jpgm, which may cause problems with extensive post-processing in PS.
The problem is the use of 8-bit colour depth. Not TIF.
 
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