Hi,
Just a
few notes on Sam Landry's issues with stochastic/FM.
RE:
"* It is very difficult
to monitor solid densities. The Press runs we experienced would have no real
solid, even on the color control bars. This was something of a surprise to us.
This presents problems in control as SWOP is monitored and fingerprinted with
target solid ink densities."
(GP)
There is no difference in monitoring solid ink densities on press between AM and
FM. Color bars arfe the same for both screeningb systems. If the solids did no
look solid - it may bed that the press operator was running at too low a solid
ink density, perhaps to compensate for the higher dot gain of a finer
screen.
RE
"* We had odd gradation shifts
and banding. These became more apparent in areas of light gradations as, lets
use the example of 15% to 1%. This caused impossible gray balance issues in snow
images as well as flesh tones and drop shadows"
(GP)
Odd gradation shifts (assuming they are not in the original file)
can be caused by improper tone reproduction curves applied during plate imaging.
They arre not a characteristic of the screening (many car brochures are printed
with FM screens precisely because they render 4/c grays more accurately). If, by
"banding" you mean shadestepping then it could indicate a problem with either
the tone rep curves, the plate imaging setup, or the press condition. Banding is
not a characteristic of FM screening.
RE: "* Certain subject matter reproduced nicely with stochastic. High contrast
high detailed images were the best target subjects for
stochastic"
(GP) In a properly calibrated and printed
environment their is virtually no difference, at normal viewing distances, in
the appearance of presswork run AM or FM. Where you will see a difference, if
any, is in areas where only one or two chromatic colors are used ( C, M, Y, R,
G, or B). The extra chroma of the finer FM screen will make that area appear
slightly lighter as well as more vibrant. FM is suitable for all subject matter
content.
RE: "The printer that was selling us this
process was having obvious control issues in the quality of our stochastic
printed covers. These issues were never resolved in my time in that position. We
were told many times that the issues were fixed and new test proved that in
fact, they were not. The printer could have been questionable in their abilities
with stochastic. We had constant issues with their quality compared to multiple
other printers we used. These issues with them were of conventional screened
jobs as well."
(GP)
I think that you've nailed the culprit right there. The screening
was not the problem, although it may have magnified their existing
problems.
As far as Hexachrome is concerned, the latest Pantone
Hexachrome swatchbook was printed with Staccato (Creo/Kodak's FM
implementation). It is not good practice to mix FM and AM screens on the press
because they have different print characteristics (ink/water balance). To get
one right the other will usually suffer. The exception would be using an FM
screen for the Yellow printer in a CMYK image. This is sometimes done to
eliminate screening moire between Y/C or Y/M. A coarse FM screen would be used
(so that it has similar press response to the AM screens in the image) Because
the Yellow is difficult to see - the screen, though coarse, is also difficult to
see.
thx, gordon
pritchard
Kodak Graphic Communications Canada
Company Gordon Pritchard
| Value In Print Marketing
Manager | Tel:
+1.604.351.2437 | email@hidden | http://graphics.kodak.com
|