Fake Stochastic Screens In Offset-Litho

After a few years the Australian stamp printers skipped from fake stochastics to real stochastic screens. In a few other countries we also could find these fakes e.g. Danmark.

The latest issues of Belgium show a combination of fake stochastics plus high-definition cross screens!

Issued 22.10.2018



to be continued...

The black [under an angle of 15 degr.] and the 1st magenta [45 degr.] prints are normal; the second magenta and the cyan are fake stochastic - the screen dots are aligned at 75 deg. [magenta] or 15 deg. [cyan] BUT the lines show jumps!

The yellow printing dots can be seen in certain spots under a degree of 0 i.e horizontal/vertical !

But rather as a fake stochastic screen!

So, is there a cost advantage for the printer in using a faux stochastic screen over using a real one?

Bob,

as to the stochastic screens there is some advantage above a normal [cross] screen, but most important is often the bad quality of the original pictures which will be hidden for us.

As to the stochastic screen in general, in the beginning they processes were costly, heavily patented! That may have played a role in getting around it by using a traditional cross screen and shake it up a bit.

I still to make an inventory of the early use of stochastic screen in the postage stamp production. Germany was pretty early but seems to have dropped it totally!

Rein

For the intrigued, would one of you be kind to enough to "explain like I'm 5 years old (ELI5)" the difference between stochastic and faux stochastic screens? Thanks!

Hello Rein

Nice to see a technical post here again.

Canada Post presently uses 3 printers for stamp production.
The old reliable Canadian Bank Note Co., Lowe-Martin Group
and for the last couple of years or so Colour Innovations.


Lowe-Martin and Colour Innovations both state on their websites
that they use stochastic screening.
I don't see anything on the CBNC site about stamp printing,
they are more interested in printing currency.

http://www.lmgroup.com/services/secure-printing

https://colourinnovations.com/offset-printing/


Here are some recent examples of offset-litho from the 3 Canadian printers.

CBNC





Lowe-Martin





Colour Innovations





Are they all stochastic screening printing ?
Any fake stochastic ?

Ij stochastic screens the dots are placed at random, in fake-stochastics the dots are arranged as usual - cross screens ostly - BUT the DPI [dot per inch] is pretty high plus the screen was shaken up as I showed you on this Belgian example. The 2018 Christmas seems to have the same!

When stochastic screening was introduced there was a lot of discussion of whether this was to be an improvement. So far it was only available for offset-litho printing and in offset-litho the solution of anti-moiré had long proven the different screen angles for the 4 CMYK colours [cyan, magenta, yellow and black] like 75, 15, 0 and 45...

Only a few stamp issueing countries are steadily using a stochastic screen for their offset-litho like Australia and Canada. Other stamp printers hardly ever use that stochastic method unless the artwork they get from the designers is rather poor. And in the latter case using a stochastic screen just flatters it.....

Some examples:

German State Printers:





Swiss Post Office Printers:





Denmark Post Office Printers:





The German and Swiss screens are really stochastic, the Danish one is fake - you can see the horizontal/vertical screen still...

Belgium Christmas 2018






Magenta and cyan seem to be normal, but have a good at the magenta dots on a yellow backfground! Especially in the last image!

Thanks for the nice images Galeoptix.

The faux/fake stochastic screens do not seem to improve the sharpness, or depth (Danish example) of the offset printing. It is difficult to judge how effective this process could be because most of the examples are with stamps of modern graphic design, where the artwork is rather flat.

The true stochastic printing on the recent Canadian landscape/national parks definitives seem to give the stamps added detail and depth... so much so that they appear almost photographic. The original artwork is photographic, so there seems to be a natural advantage for the process to be used here.

It would be interesting to see the same stamp printed by different printers using the two processes. That might give a better look at the difference in quality.