QTR-Quadtone RIP

On 11/01/2012 12:06, Mel wrote:
>
> This is really related to my other recent posts and is an attempt to 
> further understand the process.
>
> This is how I re-linearized QTR_1400_UT14_IGFS_ cool and warm using 
> MIS inks to make a curve for Epson Premium Semi Gloss paper 
> (EPSG)using Windows 7.
>
> 1. Open the QTR programme.
> 2. Click on Tools>Curve Creation.
> 3. Click on File>Open>QTR_1400_UT14_IGFS_cool.qidf
> 4. Click on Open.
> 5. Click on Linearization.
> 6. Click on Clear.
> 7. Click on File>Save As>QTR_1400_UT14_EPSG_cool.qidf
> 8. Exit Curve creator.
> 9. Return to the QTR programme.
> 10. Click on File>Select Image>(navigate to the appropriate folder for)
> 21step.tif and click on this.
> 11. Select A4, Portrait, 2880 dpi, Uni-directional and the new
> QTR_1400_UT14_EPSG_cool.qidf making sure Curve Blending is at 100%
> and 21step.tif is placed near the top of the page (to allow for
> subsequent print offs).
> 12. Place an A4 sheet of Epson Premium Semi Gloss in the printer and
> click Print.
> 13. Allow to dry for several hours.
> 14. Measure the steps (I use an X-Rite 810).
> 15. Open Curve Creation again and navigate to
> QTR_1400_UT14_EPSG_cool.qidf and open it.
> 16. Click on Linearization (it should be empty).
> 17. Enter the measurements from 21step.tif, starting top left with
> the "white" (paper white)measurement, following horizontally to the
> right, then following from left to right on the next line. The
> final value (black) on the third line at the left end.
> 18. Save this as QTR_1400_UT14_EPSG_cool.qidf and Exit Curve
> Creation.
> 19. Return to the QTR programme and open
> QTR_1400_UT14_EPSG_cool.qidf,set the parameters as before and print
> off 21step.tif below the first one on the paper.
>
Looks good, except:
11. I use 1440 dpi as i found some anomalies in the density graph when 
building curves from scratch at 2880 dpi. I *think* the supplied curves 
are usually for 1440 dpi
13. I leave 24 hours - I've not tested whether this is necessary, as its 
probably going to vary from paper to paper (and ink to ink) anyway.
>
>
> I would like comments on this approach using these papers, especially 
> from Roy, Tom and David if possible.
>
> I made a few "trial" linearization curves using 
> QTR_1400_UT14_IGFS_cool.qidf as a basis but these don't appear in the 
> Profiles folder of Windows Explorer - why would this be so as they 
> appear in the QTR programme, Curve Setup, drop down menu? The "trial" 
> linearization curves also appear here, even though I managed to delete 
> them in Curve Creator - how do I delete them in the QTR programme (I 
> am using 2.7.0.0 for Windows)?
>
They don't appear in the Windows profile directory, as they aren't ICC 
profiles for general use in graphics programs, they are curves purely 
for use when printing with QTR (using qtrgui in the case of Windows - 
unlike Macintosh computers you can't print with QTR direct from 
Photoshop etc.). You need to be careful reading instructions on how to 
use QTR - its different on the two platforms. I'm not at the right 
computer at the moment, so can't tell you how to remove the curves - I 
think you just delete a file in a particular directory, but would need 
to look it up.
>
> 

-- 
mike finley photography
http://www.mikefinley.co.uk
http://words.mikefinley.co.uk



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