Digital BW, The Print

Tim,

I've been doing this by eye as well, but without the scanner idea as my scanner can 
not differentiate the lighter tones at all, and it seemed pointless.

What I do is to:

1. print out the test page with the ink levels at 100.

2. For each ink I set the ink limits individually based upon using my eyes to make 
sure there is signifcant seperation in the darkest patches. IOW I choose the darkest 
patch that seems to have a uniform step up to the next one and set the ink limit for 
that ink using that patch.

3. I print out a new calibration chart with the new ink limits and cut the grey step 
wedges into strips. Then by eye I place the lighter strip on top of the next darker strip 
to calculate the ink% for curve making.

4. I set the overlap, or what ever it's called to about 20% and make a curve and print 
out a step wedge using the new curve.

5. by eye, through some trial and error I adjust the overall gamma or the shadow or 
hightlight gamma to match my screen with a step wedge displayed at gamma 2.2


This seems to get me very very very close. If I had a densitometer, I could then run 
the "linearize" option and make a perfected curve, but I don't.

I will say that I can find no bumps in the gradient though. I'm very impressed.

-bruce

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Tim Goodwin <tgvoz@p...> 
wrote:
> QTRIP Calibrating Density with Photoshop
> 
> As I do not own nor have access to a densitometer, I am trying to 
> perform the Ink Density calibration for QTRIP v2.0 beta8 using 
> Photoshop 7 and my old Epson Perfection 1200 scanner. This is for an 
> Epson 1270 using MIS VM inks with Ebony black.
> 
> After doing the Hardware Ink Limitation Calibration(which I settled 
> on 90), I printed out the QuadtoneRIP Ink Pattern Page in Calibration 
> mode (with BOOST_K disabled). I then scanned the resulting image into 
> PS using Silverfast Ai 6. I disabled all calibration and color 
> correction in Silverfast and scanned in RGB mode converting to 
> grayscale in PS.
> 
> The problem is that my 100 Black is only 85%in PS (38 RGB). I assume 
> that I should be getting a reading of 100% or something close to it. 
> Although I can correct this in Silverfast or PS I would think that 
> this would defeat the whole purpose of the calibration process.
> 
> What have I done wrong and how can I correct this ?
> 
> Any and all help would be greatly appreciated.
> 
> Thanks
> Tim Goodwin
> 
> [Non-text portions of this message have been removed]