Vuescan Densitometer -- How?

[cschweda]

<p>I've been told Vuescan has a built-in densitometer. My understanding is that you preview the image and then (a) hold down the CTRL key while (b) left-clicking on the image area that you want to measure.<br /> I do this, but nothing seems to happen. Do other settings need to be set? Where does the measurement appear? I see the RGB values in the lower right -- and I assumed something would appear there -- but I see nothing that would indicate a measurement.<br /> Do I scan the complete image (and not attempt this during the preview?)<br /> I'm running the latest VueScan on Vista (32-bit) with an Epson 2450 scanner.<br /> I'm probably missing something obvious ...</p>

<p>(BTW -- I'm scanning 6X6 and 6X4.5 negatives in a betterscanning adjustable holder with custom cutouts. Not sure if this makes a difference.)</p>

[karl_schuneman]

<p>Try this Photo.net link<br>

<a href="http://www.photo.net/digital-darkroom-forum/00C1U0">http://www.photo.net/digital-darkroom-forum/00C1U0</a></p>

[rodeo_joe1]

<p>Vuescan might have a built-in guessitometer, but you're probably better off thinking of a number and putting a "D" after it. No general purpose program like Vuescan can know exactly what calibration look-up table to apply to your particular scanner, not without a lot of user input, such as scanning two or three known densities. But if you have a few Wratten ND filters or suchlike lying around, then you can use them to translate your scanner output to density values..... approximately.</p>