RE: VueScan: (was: Re: Measuring DMAX
Katherine, Open the file in PS and save it as a grayscale file. Then with your scanner off open the file in Vuescan and all of the density readings will be the same. The maximum DMAX value that you can read in VueScan depends on the capability of your scanner. With the 1650 I expect that value to be around log density of 2.0, which should be enough to measure the DMAX of a gum print. In my experience I'll be surprised if the DMAX of a gum print is much above 1.1. Don Bryant -----Original Message----- From: Katharine Thayer [mailto:kthayer@pacifier.com] Sent: Friday, February 01, 2008 11:46 AM To: alt-photo-process-l@usask.ca Subject: Re: VueScan: (was: Re: Measuring DMAX Thanks, but not true; my three numbers are all different; I've never gotten three identical numbers, either in 8 bit or 16 bit, or even in 1 bit! They generally range over 6 or 8 points, but sometimes as much as 12 or 15. If they were identical, do you really think I'd be asking the question? On Feb 1, 2008, at 1:23 AM, Kees Brandenburg wrote: > 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 >> >> >> > >
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