Re: FOGRA52 & i1Profiler [subject corrected]
Re: FOGRA52 & i1Profiler [subject corrected]
- Subject: Re: FOGRA52 & i1Profiler [subject corrected]
- From: Claas Bickeböller <email@hidden>
- Date: Sun, 10 Sep 2017 13:17:11 +0200
Martin,
>>
>> Why ?
>>
>> The nature of the device response is that you can either
>> have lots of yellow or you can have the result being neutral.
>>
>> Take your pick.
>>
>> i.e. the amount of yellow is correct to reproduce the desired color.
>
>
>
> In print, the result doesn’t look neutral, or natural.
>
> If you make a high GCR custom profile from FOGRA52 and proof or print the
> results to compare them to images separate using PSO Uncoated v2 they do not
> match and will not get approved by a client.
>
> They are too blue.
>
> High GCR profiles using the FOGRA47 data work better than those made from 52.
>
> If the device demanded blue blacks, why doesn’t the ECI profile generate them?
What do you mean?
——————————— ECI profile round trip
Using the FOGRA52 ECI profile with relative colorimetric intent I get
60.000000 0.000000 0.000000 [Lab] -> Lut -> 0.404592 0.319606 0.277260 0.159097
[CMYK]
50.000000 0.000000 0.000000 [Lab] -> Lut -> 0.516231 0.416335 0.338695 0.322331
[CMYK]
40.000000 0.000000 0.000000 [Lab] -> Lut -> 0.654292 0.527596 0.382775 0.585379
[CMYK]
30.000000 0.000000 0.000000 [Lab] -> Lut -> 0.991366 0.640319 0.405984 0.959954
[CMYK]
When I now check which colour results from this CMYK (so doing icclu -ff -ia) I
get:
0.400000 0.320000 0.280000 0.160000 [CMYK] -> Lut -> 55.776221 1.765123
-6.388393 [Lab]
0.510000 0.410000 0.330000 0.320000 [CMYK] -> Lut -> 46.607086 1.472108
-5.911079 [Lab]
0.650000 0.520000 0.380000 0.580000 [CMYK] -> Lut -> 37.074239 1.163277
-4.468112 [Lab]
0.990000 0.640000 0.400000 0.960000 [CMYK] -> Lut -> 28.472357 1.044766
-0.644196 [Lab]
The result for CIELAB 30/0/0 could be called neutral (in terms of being close
to a*=b*=0) but already the result from 40/0/0 is what I’d call bluish.
——————————— Other FOGRA52 ICC profile round trip
Doing the same with a profile made with a different profiler I get
60.000000 0.000000 0.000000 [Lab] -> Lut -> 0.192258 0.139751 0.077765 0.434442
[CMYK]
50.000000 0.000000 0.000000 [Lab] -> Lut -> 0.282647 0.195927 0.087893 0.587088
[CMYK]
40.000000 0.000000 0.000000 [Lab] -> Lut -> 0.486236 0.319710 0.111802 0.740444
[CMYK]
30.000000 0.000000 0.000000 [Lab] -> Lut -> 1.000000 0.637776 0.260741 0.924599
[CMYK]
and
0.192200 0.139000 0.077000 0.434000 [CMYK] -> Lut -> 55.783325 1.637784
-6.614620 [Lab]
0.283000 0.196000 0.088000 0.587000 [CMYK] -> Lut -> 46.345132 1.563961
-5.723870 [Lab]
0.486000 0.320000 0.112000 0.740000 [CMYK] -> Lut -> 37.031277 1.421238
-4.754050 [Lab]
1.000000 0.638000 0.261000 0.925000 [CMYK] -> Lut -> 28.975247 1.187015
-1.881533 [Lab]
If we compare the results for mapping CIELAB grey relative colorimetric we get
delta-b* values for
30/0/0 -> -1.24
40/0/0 -> +0.2
50/0/0 -> -0.3
60/0/0 -> -0.2
So a very similar result compared to the ECI profile, not?
Another story is if you like the result or not.
As Andy pointed out, relative colorimetric in ICC language means that all
colours are scaled to the media white point in CIEXYZ space.
In other words, there seems to be an underlying assumption that the paper white
point gets the adaptation white point and hence a grey balance following the
mediarelative a*/b* axis is perceived as neutral.
If I understand you correctly this is not matching your expectation.
IMHO there is only one solution although you call it „voodoo“:
You need to use a perceptual mapping that is mapping the grey axis to what you
expect.
BTW: Jürgen Seitz's example using a GMG DVL profile is nothing else than a
perceptual mapping. If they followed the ICC rel.col. approach they’d have
ended up with the same result.
You could also bake this into an ICC profile. It’s about the mapping not the
encoding.
Example result of an ICC profile made from FOGRA52:
100.000000 0.000000 0.000000 [Lab] -> Lut -> 0.000000 0.000016 0.000026
0.000000 [CMYK]
90.000000 0.000000 0.000000 [Lab] -> Lut -> 0.014219 0.004111 0.055549 0.071615
[CMYK]
80.000000 0.000000 0.000000 [Lab] -> Lut -> 0.025515 0.004922 0.109531 0.161295
[CMYK]
70.000000 0.000000 0.000000 [Lab] -> Lut -> 0.030263 0.008299 0.120143 0.313838
[CMYK]
60.000000 0.000000 0.000000 [Lab] -> Lut -> 0.051484 0.022548 0.134936 0.467605
[CMYK]
50.000000 0.000000 0.000000 [Lab] -> Lut -> 0.093016 0.038174 0.155986 0.625049
[CMYK]
40.000000 0.000000 0.000000 [Lab] -> Lut -> 0.171849 0.072261 0.172990 0.757199
[CMYK]
30.000000 0.000000 0.000000 [Lab] -> Lut -> 0.267693 0.111687 0.179354 0.843397
[CMYK]
20.000000 0.000000 0.000000 [Lab] -> Lut -> 0.419455 0.176708 0.222435 0.915680
[CMYK]
10.000000 0.000000 0.000000 [Lab] -> Lut -> 0.615754 0.259249 0.289859 0.965992
[CMYK]
0.000000 0.000000 0.000000 [Lab] -> Lut -> 0.849600 0.357592 0.392777 0.999987
[CMYK]
0.000000 0.000000 0.000000 0.000000 [CMYK] -> Lut -> 93.500024 2.496975
-9.999705 [Lab]
0.014000 0.004000 0.056000 0.072000 [CMYK] -> Lut -> 86.954369 1.180527
-4.501073 [Lab]
0.026000 0.005000 0.109000 0.161000 [CMYK] -> Lut -> 79.905673 0.032551
-0.183074 [Lab]
0.030000 0.008000 0.120000 0.314000 [CMYK] -> Lut -> 70.025270 -0.093927
0.018392 [Lab]
0.051000 0.022000 0.135000 0.468000 [CMYK] -> Lut -> 60.028832 -0.028715
0.002454 [Lab]
0.093000 0.038000 0.160000 0.625000 [CMYK] -> Lut -> 50.039013 -0.105061
0.249806 [Lab]
0.172000 0.072000 0.173000 0.757000 [CMYK] -> Lut -> 41.834047 0.099612
-0.323106 [Lab]
0.268000 0.111000 0.179000 0.843000 [CMYK] -> Lut -> 36.764165 0.140901
-0.566765 [Lab]
0.420000 0.180000 0.220000 0.915000 [CMYK] -> Lut -> 33.077930 0.208292
-0.587383 [Lab]
0.615000 0.259000 0.290000 0.965000 [CMYK] -> Lut -> 30.801452 0.080759
-0.418828 [Lab]
0.850000 0.360000 0.390000 1.000000 [CMYK] -> Lut -> 29.111992 0.092626
-0.211476 [Lab]
Does this fit better to what you’d expect?
Nice weekend
Claas
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