V.1 The colors in processed images don't match the original
binuscan is NOT a colour calibration system, in the sense that KPCMS or
Colorsync are.
The most fundamental difference is that the IPM analyses aspects of the
image such as exposure, colour cast, overall contrast and range - and
then corrects for these.
A simpler ICC based system will accurately reproduce a bad scan, based
on the known colour characteristics of the scanner and printer - binuscan
will try to correct the image as well.
V.2 CMYK images look "off" when viewed in Photoshop
binuscan uses its own proprietory method to generate CMYK separations,
reproducing a far wider range of colours than Photoshop's own system.
When Photoshop displays a CMYK image, it must first reconvert the image
back to RGB using its own Monitor, Printer and Ink settings - the resulting
image is often innacurate, looking slightly oversaturated, oversharpened
and too heavy in the shadow areas.
RGB images can be viewed far more accurately - CMYK images can only be
confidently viewed on proofs or prints (we support this view for images
generated by ANY program - there are too many compromises required to
accurately view CMYK files).
binuscan ColorCorrect, however, provides a safe viewing window for binuscan
CMYK files, because it actually displays an accurate matching RGB preview.
V.3 Images appear over-sharpened
Sharpness is extremely difficult to judge on screen, even when viewing
at 1:1 - in general, a good scan from a drum scanner appears too sharp
on screen.
Again the only way to accurately judge is in a proof or final print.
V.4 Should I have to change the module settings?
In our experience, no - an enormous amount of time and many proofs are
used to optimise the modules, and we can only very rarely improve on the
standard settings.
Users of the Pro Toolkit (PTK) package can create precise RGB curves for
their scanners, meaning that any slight color cast in that unique scanner
is compensated for.
ColorPro users can compensate for their scanners color balance by making
slight adjustments to up to two of the C, M and Y Gamma Exposure controls.
The single most common reason for incorrect color results is that the
instructions for configuration of the scanner driver (achieving a raw
scan) have been misinterpreted.
V.5 How do I compensate for images being too dark or too light?
Although scanners have generally consistent exposure (most calibrate for
this during every scan) different printing techniques affect the lightness
and contrast of an image.
Simple corrections for lightness can be made either
- with the Global Gamma Exposure control (increasing the value lightens)
or
- by adjusting the midpoint of the CMY output curves (lowering the
midpoint lightens).
Compensating for specific print conditions is covered below.
V.6 How can I match my printer's specifications, for example dot gain?
Printer's specifications are often a confusing mix of conventional measures
Adobe's Photoshop package includes some parameters, such as a single Dot
Gain measure and basic UCR and GCR controls, however printer's often specify
three Gain values per ink, request polychromatic separations etc.
binuscan's approach vastly simplifies these issues - in particular, the
"tolerance" of the default "BINUSCAN" separation table has resulted in
its use by up to 80% of users.
V.7 Consistent separations
ColorPro can reproduce a much broader range of colours in CMYK, and can
accommodate widely varied printing conditions.
The separations are designed to give consistent composite colour results
irrespective of the separation type - UCR and GCR separations will be
almost identical when proofed together.
Certain separations, in particular "BINUSCAN", cannot be edited - all
of the others are fully customisable.
V.8 "Conventional" print conditions
binuscan's default separation table and normal UCR and GCR parameters
are suitable for all conventional print conditions, using sheet or web
offset presses, coated and uncoated media with midtone dot gain ranges
of 5-20%+.
Total ink coverages are normally in the range 260-290%.
V.9 Coldset and heatset web presses for newsprint
These print conditions are far more complex, requiring compensation for
the high midtone dot gain (typically 35%), severe ink limits and very
low total ink coverages (eg 220%).
In these cases, try the following: Ink limits - correct for these using
the CMY Output correction curves.
Set the minimum dot % for each of the inks.
For the maximum ink %, set the maximum point on the curve to around 10%
higher than the printer spec for each colour.
Dot gain - lower the mid point of each of the CMY correction curves to
compensate for dot growth, typically reducing the 50% horizontal (input)
values to around 32-35% vertically (output).
Separation type - although printers are more likely to recommend GCR,
this will generate too heavy a black plate for most newsprint presses.
UCR allows lower TIC values - we normally increase the requested TIC by
15% and the black maximum by 10%.
UCR generates separations that are often described as "skeleton black".
If three-quarter tone and shadow detail are very important, UCR may not
be suitable, as these areas will be primarily rendered in CMY.
Instead, careful use of GCR will produce K-only shadow detail.
One final hint - the K bar in the separation control screen simulates
the black plate if a neutral CMY+K strip were to be printed.
This adjusts as the separation controls are changed, giving great feedback
when setting these parameters.
V.10 Flexo printing
The Dot Gain needs to be around 32-33%, and the contrast a bit higher.
The Screens start at 5% and the yellow curve is much important.
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