[argyllcms] Re: Print Validation
- From: Jan-Peter Homann <homann@xxxxxxxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Sat, 18 Oct 2014 15:23:05 +0200
Hello Robert,
The proofing workflow Graeme is describing adresses normally a source
gamut which is smaller than the target gamut and an absolut colorimetric
match from source to target.
You are using AdobeRGB as a source, which has several colors, which are
out of gamut of the target colorspace (printer)
you also using the relative colorimetric intent.
...
If you want to test, how good matches a printer the printer profile:
create a a print wedge in the printer colorspace
(same colorspace you have the printer profile with)
create a text file with the same colors as the print wedge
convert the text file with fakeread to L*a*b*
print the print wedge in device mode mode (colormanagement off)
measure the print wedge
compare the measurement results with the fakeread output
Regards
Jan-Peter
Am 17.10.14 18:39, schrieb robert@xxxxxxxxxxxxxxxxxx:
> Hi Graeme,
>
> I've tried the workflow you've suggested (below) to check my print accuracy
> and my results are well off. Here are the first few (worst values):
>
> No of test patches = 100
> File 0 Chose patch 1 as white, xyz 0.964203 1.000000 0.824905
> File 1 Chose patch 1 as white, xyz 0.837679 0.872949 0.741557
> L*a*b* white reference = XYZ 0.964200 1.000000 0.824900
> 21: 18.038560 25.951478 22.489887 <=> 39.803954 11.831945 -35.079664 de
> 37.269236
> 28: 34.185591 -67.085881 -6.455341 <=> 62.944388 -90.026713 44.587042 de
> 34.884374
> 41: 40.524868 -33.803806 -52.438105 <=> 65.223756 -60.678084 -21.994298 de
> 29.777970
> 26: 52.908776 -78.403017 -17.947748 <=> 71.957265 -79.305174 41.137194 de
> 29.656735
> 12: 57.830887 -42.597937 -57.500006 <=> 76.080635 -62.957608 -8.243975 de
> 27.776304
>
> So I'm clearly doing something drastically wrong!
>
> I would really appreciate it if you would have a look at these commands to
> see where the mistakes:
>
>
> targen -v -d2 -G -f100 iPFTest
> copy iPFTest.ti1 iPFRef.ti1
>
> fakeread -v -Ir iPF6400_HP_ID_Satin.icm iPFRef
>
> printtarg -v -r -ii1 -a1.0 -T300 -M6 -pA4 iPFTest
> cctiff -v -e AdobeRGB1998.icc iPFTest.tif iPFTestO.tif
> move /Y iPFTestO.tif iPFTest.tif
>
>
> Pause Print iPFRef.tif using iPF6400_HP_ID_Satin.icm profile and Rel. Col.
> chartread iPFTest
>
> Pause The test results will be in iPFValidate.txt
> colverify -v2 -N -k -s -w -x iPFRef.ti3 iPFTest.ti3 >iPFValidate.txt
>
> I'm printing iPFTest.tif using Photoshop, RelCol to iPF6400_HP_ID_Satin.icm.
>
>
> Many thanks!
>
> Robert
>
>
> -----Original Message-----
> From: argyllcms-bounce@xxxxxxxxxxxxx [mailto:argyllcms-bounce@xxxxxxxxxxxxx]
> On Behalf Of Graeme Gill
> Sent: 15 October 2014 14:26
> To: argyllcms@xxxxxxxxxxxxx
> Subject: [argyllcms] Re: Print Validation
>
> robert@xxxxxxxxxxxxxxxxxx wrote:
>
>> I've tried your first method and it's just fine. I'll try the variation:
> is
>> that effectively equivalent to using profcheck?
>
> Yes, it's going to be similar.
>
>> I don't really understand your last suggestion.
>
> In a proofing type workflow, the aim is to get a printer (or other
> display device) to emulate some particular target colorspace. You do
> this by transforming the colors you want to reproduce through a source
> profile (which defines the target you are trying to emulate) and the
> device profile.
>
> If you want to check how accurate your proofing system is,
> then the type of thing you might do is generate a test
> set in the target device colorspace, and run it through the
> source profile with fakeread to create the reference .ti3 file.
>
> Then you run the same colors through your proofing workflow
> (e.g. create a .tif using printtarg, then apply the source
> to printer device link to the .tiff using cctiff and print it,
> or run the .tif through whatever ICC based workflow you have
> setup for proofing), measure the result and compare
> the .ti3 to the reference using colverify.
>
> Graeme Gill.
>
>
>
>
>
--
homann colormanagement ----------- fon +49 30 611 075 18
Jan-Peter Homann -------------- mobile +49 171 54 70 358
Herzbergstr. 55 FG 3.01 -- http://www.colormanagement.de
10365 Berlin ---------- mailto:homann@xxxxxxxxxxxxxxxxxx
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