Re: VueScan: (was: Re: Measuring DMAX

[Kees Brandenburg <ctb@zeelandnet.nl>]

Hi Katherine,

Missed your first question. When you scan in grayscale (set bits per  
pixel to 16 or 8 in the input tab) you still get 3 numbers but they  
are identical. You can use either one as your density reading. This is  
different then a real visual density measurement by a densitometer, as  
there is a RGB to grayscale conversion - but in fact it's pretty close.

kees


On 31 jan 2008, at 17:36, Katharine Thayer wrote:

> On Jan 23, 2008, at 5:25 PM, Katharine Thayer wrote:
>
> > On Jan 15, 2008, at 12:46 AM, Kees Brandenburg wrote:
> >
> >
> > > Hi Marek,
> > >
> > > Vuescan <http://www.hamrick.com> can do that. First check the  
> > > 'Enable Density Display' option in preferences. Then point your  
> > > mouse to a location in the scan/preview window and hold the  
> > > control key. Vuescan displays the log density readings of the raw  
> > > scan. These readings are not altered by your scanner settings or  
> > > profile.
> > Kees, I get three density numbers at any given point  whether the  
> > image is in color or black and white. Is it reading three color  
> > densities for each point, or what?  I can't see any particular  
> > relationship between the density readings and the 0-255 readings  
> > from the same coordinates (that you get when you stop depressing  
> > the control key).   Is there any way to get one density reading for  
> > a point?
> Hi folks,
> I asked this question a week ago and am still waiting and hoping for  
> an answer.  Searching the archives this morning, I found an answer  
> from Yves I hadn't noticed before, saying that in his version of  
> VueScan, if he's in black and white mode, he gets one density value.
>
> That's great, but it doesn't answer my question, since in my version  
> of VueScan, as I said in the earlier post, I get three density  
> values whether I'm scanning in color mode or in black and white  
> mode.  I was hoping someone knew a way to fix that.  I haven't  
> actually purchased the VueScan; I'm just using the downloaded  
> version for the purpose of reading density values.  If it actually  
> worked, I might be tempted to purchase the program, but so far it's  
> not terribly useful to me to have three different density values for  
> any given point.  This is with VueScan 8.4.56,  the version of  
> VueScan that is supposed to work for Mac 10.4.
> Katharine