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


Richard Brennan
 

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.

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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 “melt� with any solvents we typically use to settle decals.

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