spectro/printread
Summary
Read a printer test chart using an instrument, to create a .ti3 data file.
Usage
printread [-options] outfile
-v
Verbose mode
-d
Print debug diagnostics
-c comport Set COM
port, 1..N (default 1)
-i 41 | 51 | SS Choose target instrument
41 = DTP41, 51 = DTP51, SS = Spectrolino or
SpectroScan or SpectroScanT
-t
Use transmission measurement mode
-e
Use emissive measurement mode (absolute results)
-x [lx]
Take external values, either L*a*b* (-xl) or XYZ (-xx).
-n
Don't save spectral information (default saves
spectral)
inoutfile
Base
name for input[.ti2]/output[.ti3] file
Usage Details
The -v flag causes extra information to be
printed out during printread
operation.
The -d flag causes serial communications
diagnostics to be printed to stdout. This can be useful in tracking
down why an instrument can't connect.
Normally instruments are connected via a serial
communication port, and the
port used should be selected by supplying the correct parameter to the -c
flag. If you invoke printread
so as to display the usage
information (i.e. "printread -?" or "printread --"), then the
discovered
serial ports will be listed on Windows and Mac OSX systems.
The type of instrument is normally specified when
creating the test chart
with printtarg,
but it can be overridden by using the -i flag. Note that
specifying -iSS will enable automatic detection of a Spectrlino (hand
held), SpectroScan or SpectroScanT.
If using an Xrite DTP41T, and printing onto transparent
or back lit media,
use the -t flag to operate the instrument in transparency mode.
If using a Spectrolino (handheld), this triggers a fake transparency
mode, that uses a separate backlight (such as a light box). The
instrument will be used to calibrate the level of backlight, and use
this to compute the transparency of the test chart samples. Note that
for good transparency values, the backlight level needs to be neither
too bright not too dark, should ideally be incandescent rather than
fluorescent (since fluorescent lights often have big dips in their
spectrum), and ideally should be of uniform brightness over the
measurement area. If using the SpectroScanT, the -t flag operates the instrument in
transparency mode, each reading being manually triggered.
If using an instrument that supports an emissive
measurement mode (such as the Spectrolino), then the -e flag enables this measurement
mode, and the values recorded will be absolute XYZ values. This can be
used for media such as backlit film, measuring it on a lightbox, so as
to capture the actual illumination characteristics of that particular
media.
The -x flag
causes printread to expect values to be entered for each reading,
rather than using an instrument to do the measurements. This mode
is ideal if your instrument is not supported by Argyll. Either XYZ or
L*a*b* values can be entered, depending on what option follows -l,
-lx to specify XYZ values, or -ll to specify L*a*b* values. XYZ
values are expected to be scaled to a maximum of 100. It is possible to
navigate about the test values being measured, so as to do them in any
order, as well as re-do values, in case of any mistakes.
By default spectral information as well as D50
standard observer XYZ values
will be recorded for each test patch, when such readings are available
from a device. The spectral readings allow for
choosing
a non-standard viewing illuminant, a non-standard observer model, or
the use of the Fluorescent Paper Whitener Additive
compensation
when creating the profile. If the spectral readings are not needed,
then
prinread operation can be speeded up by specifying the -n flag.
The inoutfile parameters should be the base
name of the .ti2 file,
and printread will output an .ti3 that has the same basename and the
.ti3
extension.
Discussion
When used with an Xrite DTP41 or DTP51 strip reading instrument,
printread
will first establish communications with the instrument, and then set
it
up ready to read the strips. The strips are labeled A to ZZ, and for
each
strip it will prompt:
About to read strip XX :
where XX is the strip label. You should line the appropriate strip up
in
the machine, and press its button. Since there is a slight delay
between
printing the "About to read" message and issuing the strip setup to the
instrument,
the button should be pressed a little after the message is displayed.
If the strip is read successfully, the line will be completed with:
About to read strip XX : Strip
read
OK
If there is an error of some sort, a message will be issued, and you
will
be asked whether to abort the chart reading, or retry the
failed strip:
About to read strip X : read_strip returned
'Strip
misread' (Bad reading)
Strip read failed due to misread
Hit Esc to give up, any other key to retry:
If the strip is read successfully, but the patches values don't seem to
be reasonable, you will get the following type of response:
About to read strip XX :
Seem to have read strip YY rather
than
XX !
Hit Return to use it anyway, any other key to retry:
If you are sure you lined up the correct strip, then hit return,
otherwise
line the appropriate strip up again, and hit some other key (ie. space).
You can abort the whole process at any time by hitting Escape.
When you are using an XY table type instrument, such as a Gretag
SpectroScan,
printread will first establish communications with the
instrument,
and then set it up ready to read the chart. You will be prompted for
each
sheet with a message such as:
Please make sure that the white reference is in slot
1, then
place sheet 1 of 4 on table, then
hit return to continue, Esc to give up
After hitting return you will be prompted to line up three squares on
the
sheet, one at a time:
Using the XY table controls, locate patch A1 with
the
sight,
then hit return to continue, Esc to give up
On completing this, the instrument will commence reading each sheet.