[filmscanners] RE: 24bit vs more

["Austin Franklin" <austin@darkroom.com>]

Hi Rob,

> "Austin Franklin" <austin@darkroom.com> wrote:
> >> Are you saying this applies when using Vuescan - especially with negs?
> > That is probably how every filmscanner that you or I would
> > use, works... The issue is the software (and possibly hardware), and
> > how it allows you to control this...but if you can get 8 bit data, it's
> > got to have it's setpoints set and tonal curves applied.  Some scanners
> > do the setpoints automatically in the scanner.  Some use "profiles" to
> > apply the tonal curves...
>
> I presume what you mean by tonal curves are curves applied to the data to
> correct for the behaviour of the scanner's own hardware and the
> behaviour of
> the film (ie. a film profile).

That sounds about right, but tonal curves also correct for exposure and any
other tonal changes you want to make to the image.

> Maybe I'm not understanding what "set
> points" are.  I thought you meant black and white points but now I'm not
> sure.

Yes, setpoints are the black and white extents of the image.  The black
setpoint and the white setpoint make up the two setpoints.

> >> Or are you assuming the sort of interface that Nikonscan provides?
> > I'm not assuming any specific interface...
>
> Another question then - do you use Vuescan?

No.

> Because my
> understanding of the
> original rationale behind vuescan (which has shifted a little
> over time) was
> to get the most possible useful information out of the scan, and
> leave the a
> lot of the contrast and tonal correction to editing later.

Well, I've been around since long before Viewscan...and IMO, Viewscan was
simply a scanner program that was better (in some instances) a LOT better
than any of the programs that came with the low end scanners of the
time...and allowed people to get better scans from low end scanners.

> Maybe Ed has
> changed his rationale completely over the years, but I don't
> recall him ever
> recommending that you should do all the image tonal manipulation
> in Vuescan
> and virtually none of it in an editor afterward.

I don't konw what Ed recommends or not, aside from buying his program...nor
am I really too concerned it...  I also don't know how good the setpoint and
tonal tools are in Viewscan, but as I've said, you should either get the
setpoints and tonal curves "right" (requiring none to little modification
later) in the scanner software, or use raw scan data and do the setpoints
and tonal manipulation in your image editing program of choice.

> >> OK, then I think we agree?  Other than what you mean by "raw data".
> >Typically, when you get high bit data from the scanner, it's raw
> data.  Raw
> >data specifically means the setpoints have not been set, or the tonal
> curves
> >applied.
> >What do you think raw data means?
>
> I would have taken raw data to mean exactly what it says - the bytes
> produced by the scanner with no manipulation whatsoever, meaning
> you'd have
> to remove the neg mask, invert and do tonal correction in an editor.

Correct.  That's not different than what I said, except my statement is
descriptive of what the raw data is, yours is what the raw data
requires...except you're missing setting setpoints, which really has to be
done before tonal correction.

> Perhaps my view of "raw" is skewed by being a programmer or using Vuescan;
> whose raw files are exactly as I described above.

Raw data is exactly as I have described it.  You can give it any additional
attributes you want...

> More
> importantly, the raw
> data is useless to me if I want to take advantage of the scanner's IR dust
> removal feature.

I have no need for any features like that, but my understanding is what
yours is as well, you can't use those types of "features" with raw
data...unless the scanner also passes the IR data to the scanner application
along with the raw data.  The IR data is simply a fourth channel, and could
easily be passed on if designed to do so.

Regards,

Austin

----------------------------------------------------------------------------------------
Unsubscribe by mail to listserver@halftone.co.uk, with 'unsubscribe 
filmscanners'
or 'unsubscribe filmscanners_digest' (as appropriate) in the message title or 
body