Re: Decal Paper/Ink [was:setting solution] options


John Hagen <sprinthag@...>
 

Richard,
A very well thought out message indeed.
However, you missed screen printing of decals.
This process, once a mainstream method for waterslide decals, still has some users. And, with advancements in technology, they are much higher in resolution than early days.
And they can print multiple layers, allowing a white under coat for opaque colors. But, the current crop of machines are expensive, and it can still be time consuming process.
Also, they use photo etched screens for each design, one for each color used. That drives the cost up for all but large numbers of decal sets.
Offset printing use photo etched metal plates, albeit it not one per color.
If you order from Microscale a minimum order of 200 sets (sheets really) is required.
Inkjet, Laser, UV-LED and Alps printers print directly from a file. No etching or photographing of artwork necessary.
Design the artwork using a SVG format (Scalable Vector Graphic) and send it to the printer. Depending on the print method, the artwork may use one layer for all colors, two layers, one for white and one for colors, or, for Alps one layer for each color to be printed. It can be done with the two layer method, and many have been done that way, but for the sharpest decals the best way is to use spot color printing which equals one layer per color.
Any method requires multiple passes of color for opaque colors, except black or, in Alps case, metallic colors. Since most of us are interested on model railroad decals, there is little need for metallic colors.
Far and away the best and really only choice method for basement or garage printers is the Alps. Back in the day, smaller printers could use screen printing for a relatively small investment but it was a much more time and money consuming process. I've watched Don Manlick do some printing, and it was way more involved that Alps printing. And his was a very basic set up. BTW, I've done some artwork for him, again in vector format, but I supplied it to him camera ready, which meant at 200% the final size.
It is easy to get some rather thick images with an Alps if one is not really up on their abilities. There were a lot of poorly made Alps decals printed by people that used photographs for artwork or went through the effort to create artwork using photo programs without understanding the ins and outs of doing so. B ut for the guy that knew or learned how to use a vector program, Adobe Illustrator and CorelDRAW being the most common, and learned the idiosyncrasies of an Alps, very high quality decals can be printed.
BUT, the technology is old, the printers are fragile as hell, especially the print head, colors are limited, the highest resolution possible is 600 dpi, good twenty years ago but in today's world, minimal and the ink supply is weak and getting more expensive by the day.
I am looking for someone who can print my artwork so it will be opaque and easily to apply so the rivets and other detail on the model are not hidden.
So far I haven't found one that can do as good a job as my Alps printers. My best bet is to find a printing company that uses a hi-res screen printer. But they are rare and into doing such small jobs.
If you order from anyone, get the smallest order as possible and then apply them yourself on a model to be certain they will work out as you need.
John Hagen

-----Original Message-----
From: main@RealSTMFC.groups.io [mailto:main@RealSTMFC.groups.io] On Behalf Of Richard Brennan
Sent: Thursday, May 31, 2018 1:11 PM
To: main@RealSTMFC.groups.io
Subject: Re: [RealSTMFC] Decal Paper/Ink [was:setting solution] options

All

There are two factors beyond the choice of
setting solution for any wet-slide decal that affect conformability:
- The decal paper formulation
- The ink thickness and technology

Paper:
The 'paper' backing itself is rarely the issue;
but there are many variations in the (usually)
transparent carrier film and the water-soluble adhesive layer.
The carrier film can be thicker or thinner (e.g.
ThinFilm) and the water-soluble material may vary by manufacturer.
Compared to Laser-compatible paper, Ink-Jet paper
has material at the surface which allows the
jetted dot of ink to adhere... but not run.
Laser and ALPS printers don't transfer wet, so
they do not need a semi-absorbent surface.
The material type and the age of the decal used
are the main determinants of how much conformability is possible...
facilitated by setting solutions which work
differently on the various films, but ink thickness can play a role as well.

Ink:
There are currently four major technologies being
used for direct digital printing of decals: Ink-Jet, Laser, ALPS, and UV-LED.

- Ink-Jet printers 'Spit' tiny drops of ink at
the paper. To prevent smearing… overcoat with 'Krylon' spray or ‘Future’
In general, Ink-Jet white is not supported - the
ink colors assume use of a white background

- Laser printers thermally bond static-charged
toner powder to media… and colors assume use of a white background.
Until recently, this meant no white - but
recently GhostWhite in Germany has developed
WHITE toner cartridges for HP and other color laser printers.

- ALPS Micro-Dry printers thermally transfer
colors from ribbons to the decal surface, and
print colors PLUS white and metallic from multiple ribbons.
The ALPS had the unique ability to print a layer,
retract the media, and over-print additional
colors while maintaining alignment.
The ALPS is 1990's technology, the printers are
no longer manufactured, and the ribbons, while
still in the supply chain, are becoming scarce.

- UV-LED - Think of a 3D color printer…
working in 2D. UV-LED is an InkJet-type
technology… but uses UV light for instant curing of of UV-sensitive resin ink.
Most UV-LED printers can print and cure a white
dot… then immediately overprint and UV cure a 2nd
color dot in alignment with the first.
The pricing for UV-LED is not at the hobby (or
even garage manufacturer) level; these are found
at local commercial print shops.
I've had decals printed on a Mimaki JFX, which
prints 8 ink colors, including white, at 1200dpi...
The Mimaki is somewhat size-constrained, as it
will only print up to 4 by 8.... wait a minute... that's 4 by 8 FEET!!!
NB. Under magnification... a UV-LED print will
show MORE ink thickness than the other technologies...
and since it is UV cured resin, larger areas will
have negligible 'stretch' for surface conformity.

So: Solve for 'n' (where n - number of variations - is large)...

I hope this sheds some light on what modelers are
looking at when they pick up and apply that next decal...
any why there is so much difference in the
potential for conforming to sheathing boards,
rivets, and other surface details.

My 2-cents... Comments/Clarifications Welcome.

----------------------------------------------------------------------------
Richard Brennan - TT-west
www.tt-west.com
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At 05:16 PM 5/30/2018, Pete C wrote:
There was a thread several months ago that
talked about those decals and having very thick
inking and would not “meltâ€

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