1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>fakeread</title>
<meta http-equiv="content-type" content="text/html;
charset=windows-1252">
<meta name="author" content="Graeme Gill">
</head>
<body>
<h2><b>spectro/fakeread</b></h2>
<h3>Summary</h3>
Simulate the measurement of a devices response, using an existing
device profile, or measured test point data set. The device profile
can be either an <a href="File_Formats.html#ICC">ICC</a> or <a
href="File_Formats.html#MPP">MPP</a> profile, or the data set can
be a <a href="File_Formats.html#.ti3">.ti3</a> file. A device link
separation or color space conversion can be applied before the
print/measure simulation, as well as device calibration or
inverse calibration curves.<br>
<br>
<b>fakeread</b> can be useful for creating a data set from an
existing profile to re-create a different style of profile (i.e.
create a cLUT profile from a matrix profile), for creating synthetic
data sets with known amounts of randomness for testing profile
creation against a perfectly known ideal, or for creating
verification test sets for checking colorimetric colorspace
emulation against.<br>
<br>
The options below are in the order of color processing that fakeread
performs.<br>
<h3>Usage</h3>
<small><span style="font-family: monospace;">fakeread [-options] </span></small><small><span
style="font-family: monospace;"></span></small><small><span
style="font-family: monospace;"></span><i style="font-family:
monospace;">profile.</i><span style="font-family: monospace;">[icm|mpp|ti3]
</span><i style="font-family: monospace;">inoutfile</i></small><small><span
style="font-family: monospace;"><br>
-v
[n]
Verbose mode [level]<br>
-e
flag
Video encode device input to sepration as:<br>
n
normal 0..1 full range RGB levels (default)<br>
t
(16-235)/255 "TV" RGB levels<br>
6
Rec601 YCbCr SD (16-235,240)/255 "TV" levels<br>
7
Rec709 1125/60Hz YCbCr HD (16-235,240)/255 "TV" levels<br>
5
Rec709 1250/50Hz YCbCr HD (16-235,240)/255 "TV" levels<br>
2
Rec2020 YCbCr UHD (16-235,240)/255 "TV" levels<br>
C
Rec2020 Constant Luminance YCbCr UHD (16-235,240)/255 "TV"
levels<br>
-p <i>separation.icm</i> Use device link separation
profile on input<br>
-E
flag
Video decode separation device output. See -e above<br>
-Z nbits </span></small><small><span
style="font-family: monospace;"><small><span style="font-family:
monospace;">Quantize test values to fit in nbits<br>
</span></small> -k <i>file.cal</i>
Apply calibration (include in .ti3 output)<br>
-i <i>file.cal</i>
Include calibration in .ti3 output, but don't apply it<br>
-K <i>file.cal</i>
Apply inverse calibration<br>
-r
level Add
average random deviation of <level>% to device values
(after sep. & cal.)<br>
-0
pow
Apply power to device chanel 0-9<br>
-B
display.icm
Use BT.1886 source EOTF with technical gamma 2.4<br>
-b g.g:display.icm Use
BT.1886-like source EOTF with effective gamma g.g<br>
-b p.p:g.g:display.icm Use effective gamma g.g
source EOTF with p.p prop. output black point offset<br>
-g g.g:display.icm Use
effective gamma g.g source EOTF with all output black point
offset<br>
-I intent
r = relative colorimetric, a = absolute (default)<br>
-A
L,a,b
Scale black point to target Lab value<br>
-l
Output Lab rather than XYZ<br>
-s
Lookup </span></small><small><span style="font-family:
monospace;"><small><a style="font-family: monospace;"
href="File_Formats.html#MPP">MPP</a></small> spectral values</span></small><br>
<small><span style="font-family: monospace;"><small><span
style="font-family: monospace;"> -R
level
Add average random deviation of <level>% to output PCS
values<br>
</span></small> -u
Make random deviations have uniform distributions rather than
normal<br>
-S
seed
Set random seed<br>
-U
Reverse convert PCS to device, output_r.ti3<br>
</span><span style="font-family: monospace;"> </span><i
style="font-family: monospace;">profile.</i><span
style="font-family: monospace;">[icm|mpp|ti3] </span><a
style="font-family: monospace;" href="File_Formats.html#ICC">ICC</a><span
style="font-family: monospace;">, </span><a style="font-family:
monospace;" href="File_Formats.html#MPP">MPP</a><span
style="font-family: monospace;"> or </span><a
style="font-family: monospace;" href="File_Formats.html#.ti3">.ti3</a><span
style="font-family: monospace;"> profile/file to use</span><br
style="font-family: monospace;">
<span style="font-family: monospace;"></span><i
style="font-family: monospace;">inoutfile</i><span
style="font-family: monospace;">
Base name for input[</span><a style="font-family:
monospace;" href="File_Formats.html#.ti1">.ti1</a></small><small><span
style="font-family: monospace;"><small><a style="font-family:
monospace;" href="File_Formats.html#.ti3"></a><span
style="font-family: monospace;"></span></small>]/output[</span><a
style="font-family: monospace;" href="File_Formats.html#.ti3">.ti3</a><span
style="font-family: monospace;">] file</span></small><br>
<b><br>
Examples</b><br>
<br>
fakeread profile.icm testvalues<br>
fakeread -p separation.icm profile.icm testvalues<br>
<h3>Comments<br>
</h3>
<a name="v"></a>The <span style="font-weight: bold;">-v</span> flag
reports extra information, e.g. on what BT.1886 option is doing. A
level > 1 will be more verbose.<br>
<br>
<a name="e"></a>The <b>-e</b> <i>flag</i> applies a Video encoding
to the input of the separation.<small><small><br>
<br>
n
normal 0..1 full range RGB levels (default)<br>
t
(16-235)/255 "TV" RGB levels<br>
6
Rec601 YCbCr SD (16-235,240)/255 "TV" levels<br>
7
Rec709 1125/60Hz YCbCr HD (16-235,240)/255 "TV" levels<br>
5
Rec709 1250/50Hz YCbCr HD (16-235,240)/255 "TV" levels<br>
2
Rec2020 YCbCr UHD (16-235,240)/255 "TV" levels<br>
C
Rec2020 Constant Luminance YCbCr UHD (16-235,240)/255 "TV" lev</small></small><br>
<br>
<a name="p"></a>The <span style="font-weight: bold;">-p</span> <b><i>separation.icm</i></b>
option enables a device to device value conversion before converting
to expected PCS values. This might be an ink separation of a video
calibration device link. The argument is the name of the ICC device
link that defines the separation.<br>
<br>
<a name="E"></a>The <b>-E</b> <i>flag</i> applies a Video decoding
to the output of the separation.<small><small> </small></small>See
<a href="#e"><b>-e</b></a> for the list of decodings. Setting a
video encoding for output will also set quantization of 8 bits (see
-Z flag below). If your video connection is better than 8 bits (ie.
10 or 12 bits), then you may wish to raise this default.<br>
<br>
<a name="Z"></a> <b>-Z nbits </b>Normally the target device values
are floating point numbers that may get rounded and quantized in the
process of printing them or reproducing them on the display device.
If some of this quantization can be accounted for, it may improve
the accuracy of the resulting profile, and the <span
style="font-weight: bold;">Q</span> parameter allows this
quantization to be specified. The parameter is the number of binary
digits (bits) that the device values should be quantized to. An idea
of the number of bits of precision that makes its way to your
display can be obtained by using <a href="dispcal.html#R">dispcal
-R</a> If Video encoding is selected (see -E flag above), then 8
bits is selected by default. On systems using an VGA connection or
Display Port with a graphics card with VideoLUT entries with greater
than 8 bits depth, or if using the MadVR rendered with dithering,
then a higher bit depth is typically possible.<br>
<br>
<a name="k"></a>The <b>-k file.cal</b> parameter specifies a
calibration file created by <a href="printcal.html">printcal</a> or
<a href="dispcal.html">dispcal</a>, and the supplied calibration
curves will be applied to the chart device values after any
separation and before the device profile. This allows emulating a
system that uses per device channel calibration. The calibration
curves will also be included in the resulting .ti3 file, so that
they can be passed through to the ICC profile allowing accurate
computation of ink limits.<br>
<br>
<a name="i"></a> The <b>-i file.cal</b> parameter specifies a
printer calibration file created by <a href="printcal.html">printcal</a>
or <a href="dispcal.html">dispcal</a>, and the calibration curves
will be included in the included in the resulting .ti3 file, so that
they can be passed through to the ICC profile, to allow accurate
computation of ink limits. The calibration <span
style="font-weight: bold;">is not applied</span> to tchart values.
<span style="font-weight: bold;">Note</span> that if the supplied
ICC profile contains VCGT calibration curves, that these will be
included in the resulting .ti3 by default.<br>
<br>
<a name="K"></a>The <b>-K</b> <b>file.cal</b> parameter specifies
a calibration file created by <a href="printcal.html">printcal</a>
or <a href="dispcal.html">dispcal</a>, and the inverse of the
supplied calibration curves will be applied to the chart device
values after any separation and before the device profile. This
allows for undoing calibration curves that may be part of a video
calibration device link, so that the (calibrated device value)
device profile will work as expected.<br>
<br>
<a name="r"></a>The <span style="font-weight: bold;">-r</span>
parameter is a way of simulating instability in the behaviour of the
simulated printing system. The parameter supplied to the flag will
be used to scale a random offset added to the device values (after
any separation and calibration is applied). The offset will be a
normally distributed error with an average deviation of level%. A
typically value supplied might be 1.0 to simulate 1% randomness.<br>
<br>
<a name="0"></a>The <span style="font-weight: bold;">-0, -1, -2 ..
-9</span> parameters are a way of simulating changes in the
behavior of the simulated printing system. The parameter supplied to
the flag will be used to modify the device values (after any
separation, calibration and device randomness is applied) by raising
them to the power of the parameter. This applies a transfer curve to
the simulated device response.<br>
<br>
<b><a name="b"></a></b>The <b>-[b|B|g|G] [p.p:][g.g:]</b><b>display.icm</b>
series of options, substitutes an alternative EOTF (Electro-Optical
Transfer Function) for the one specified by the matrix input
profile. <b>display.icm</b> is the display ICC profile that
provides the black point that the gamma curve curves will target.
Typically these options will be used to create a verification test
set for checking the operation of a device link or 3dLut created
using <a href="collink.html">collink</a>, using the same gamma
curve parameters. See <a href="collink.html#Ib">collink -I b</a>
for a full explanation of these parameters, and <a
href="Scenarios.html#TV2">Verifying Video Calibration</a> for more
detail.<br>
<br>
<a name="I"></a>The <span style="font-weight: bold;">-I</span>
parameter allows changing the intent used in looking up the ICC
profile colors to relative colorimetric. This would <span
style="text-decoration: underline;">not</span> be used if you
intend to make a profile from the resulting .ti3 file, since
profiles are always made from absolute colorimetric measurement
values. Note that this flag does nothing if the profile is an MPP or
.ti3 file.<br>
<span style="font-weight: bold;"></span><br>
<a name="A"></a>The <span style="font-weight: bold;">-A</span>
parameter is a way of simulating devices that have a different black
point to the profile used. This only works if an ICC profile is
used, and scales the black point to the parameter value. This will
be done in XYZ space by default, and in L*a*b* space if the <a
href="#l"><span style="font-weight: bold;">-l</span></a> flag is
used.<br>
<br>
<a name="l"></a>The <span style="font-weight: bold;">-l</span> flag
causes the CIE output values to be L*a*b* rather than the default
XYZ values.<br>
<br>
<a name="s"></a>The <span style="font-weight: bold;">-s</span> flag
works if a spectral MPP file is being used as a device profile, and
causes the output to include spectral values.<br>
<br>
<a name="R"></a>The <span style="font-weight: bold;">-R</span>
parameter is a way of simulating instability in the behavior of the
simulated measuring system. The parameter supplied to the flag will
be used to scale a random offset added to the PCS values. The offset
will be a normally distributed error with an average deviation of
level%. A typically value supplied might be 1.0 to simulate 1%
randomness. <br>
<br>
<a name="u"></a>The <span style="font-weight: bold;">-u</span> flag
changes the distribution of the random offsets applied using the <span
style="font-weight: bold;">-r</span> or <span style="font-weight:
bold;">-R</span> flags, from the default standard deviation, to a
uniform deviation distribution. The level is still specified as an
average deviation.<br>
<br>
<a name="S"></a>The <span style="font-weight: bold;">-S</span>
parameter lets a particular random seed be used when generating
random offsets, so that the randomness can be made repeatable.
Normally a different seed will be used for each run. <br>
<br>
<a name="U"></a>The <b>-U</b> flag causes fakeread to read <i>inoutfile.ti3</i>
and use a backwards lookup (CIE to device conversion), saving the
result in <i>inoutfile</i>_r.<i>ti3</i>.<br>
<br>
Fakeread is useful in creating artificial test value for testing <a
href="colprof.html">colprof</a>, as well as providing one path for
turning an MPP profile into an ICC profile. It can also be used to
create a reference file for verifying against. If a <a
href="File_Formats.html#.ti3">.ti3</a> file is specified instead
of an <a href="File_Formats.html#ICC">ICC</a> or <a
href="File_Formats.html#MPP">MPP</a> profile, then the closest
matching measured points in the .<a href="File_Formats.html#.ti3">.ti3</a>
are substituted for the test values in the <a
href="File_Formats.html#.ti1">.ti1</a> file on output. If the <a
href="File_Formats.html#.ti1">.ti1</a> file is a monochrome test
file with a White device value, then an RGB <a
href="File_Formats.html#ICC">ICC</a> profile, <a
href="File_Formats.html#MPP">MPP</a> or <a
href="File_Formats.html#.ti3">.ti3</a> may be used, and the White
values will be translated to equal RGB values. If the <a
href="File_Formats.html#.ti1">.ti1</a> file is a monochrome test
file with a Black device value, then a CMYK <a
href="File_Formats.html#ICC">ICC</a> profile, <a
href="File_Formats.html#MPP">MPP</a> or <a
href="File_Formats.html#.ti3">.ti3</a> may be used, and the Black
values will be translated to equal CMY = 0, K = grey values. <span
style="font-weight: bold;">Note</span> that any calibration within
a supplied ICC profile is <span style="text-decoration: underline;">not</span>
applied during the conversion, although it will be included in the
.ti3 output (see <span style="font-weight: bold;">-k</span> and <span
style="font-weight: bold;">-i</span> flags for how apply
calibration curves during the conversion and/or include a specific
calibration curves in the output).<br>
<br>
If a separation device profile is provided (e.g. from CMY ->
CMYK, or perhaps CMYK->CMYK, to simulate a color correction step
before "printing", or perhaps a Video RGB->RGB calibration link)
then this will be applied to the .ti1 device values, before
converting the the device values into .ti3 PCS values.<br>
<br>
Note that a .ti3 file can be renamed to be .ti1 and fakeread will
treat it as if it was a .ti1.<br>
<br>
<br>
<br>
<br>
</body>
</html>
|
