White paper l 31 January 2013 I LUX Membrane 200

LUX with Membrane 200: Engineered Surface Roughness Improves

Solid Print Quality

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White paper l 31 January 2013 I LUX Membrane 200

EXECUTIVE SUMMARY

MacDermid LUX membrane and exposure technology delivers a

unique flat-topped dot shape that improves print quality and

consistency, while delivering exceptional versatility for the

platemaker.

Using LUX Membrane 200, we can emboss an engineered

surface texture into plates made with LUX, which allows solid ink

density (SID) to be increased and mottle to be decreased. This

effect is evident in plates processed by both solvent and Lava

thermal processing methods.

The use of Membrane 200 is a quick and effective means of

improving solid print without the need to add special screening to

artwork, while retaining all the advantages of the LUX dot

structure throughout the remainder of the tone range.

LUX Membrane 200 boosts solid ink density (SID) when used to image plates processed with solvent or Lava thermal systems

LUX Membrane 200 reduces print mottle when used to image plates processed with solvent or Lava thermal systems

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White paper l 31 January 2013 I LUX Membrane 200

Ink: making the most from the least

The amount of ink applied to a flexo plate on press is determined

by the volume of the anilox roll, so changes in anilox volume will

have a profound influence on color density. However, for a

variety of economic and operational reasons, it is preferable to

use the minimum amount of ink required to achieve the needed

print quality. Doing so obviously reduces ink costs, but perhaps

even more importantly, it allows crisp reproduction of halftones

and more consistent (i.e. “cleaner”) print runs.

However, the amount of ink applied to the plate is only half the

story. The way that the ink is distributed on the surface of the

substrate plays a major role in its appearance as well. It is

during the ink transfer step that the plate can play a major role in

improving both the solid ink density (SID, the intensity of the

color) and the uniformity (most commonly measured as mottle)

of the ink on the package.

The LUX Process

LUX adds a single step to digital flexo platemaking, using a

lamination process to cover the digital mask after ablation, prior

to UV exposure (see workflow diagram below).

The LUX process adds a lamination step to the platemaking workflow

Lamination of the LUX membrane blocks the effects of oxygen

on the photopolymer during UV-induced crosslinking, causing

three major differences compared to standard digital

platemaking:

1. LUX dots have a flat top, but retain the steep shoulder

angled of digital dots. This combination of geometric

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White paper l 31 January 2013 I LUX Membrane 200

factors gives LUX dots exceptional stability and low dot

gain characteristics.

2. LUX dots are ‘type high’, meaning that dot tops are the

same height as solids. Press startup is simplified

because all print elements contact the substrate at the

same impression level.

3. LUX allows the photopolymer to image 1:1 to the mask

image. There is little or no bump curve, and the mask

image is translated into the photopolymer with a high

degree of fidelity.

The print benefits of the LUX dot shape have been proven

repeatedly. This new class of dot shape has become an

enabling technology for advanced screening because of the

exceptional stability of LUX highlight dots. In addition, the LUX

dot shape reduces the impression sensitivity of the plate, giving

more consistent print results throughout a run and from run-to-

run with the same plate.

Lamination allows surface modification

The LUX lamination process includes the ability to modify the

surface of the plate by embossing a pattern into the unexposed

photopolymer. This patented LUX capability is unique; no other

flat top dot process can achieve plate surface modification

directly.

There are two membranes available for LUX – Membranes 100

and 200. LUX Membrane 100 is a smooth membrane that gives

the LUX dot structure and 1:1 imaging, with a surface very

By blocking oxygen and shaping the UV light, LUX creates dots with flat tops, steep shoulders, and 1:1 fidelity with the mask image

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White paper l 31 January 2013 I LUX Membrane 200

comparable to standard digital plates. LUX Membrane 200

imparts an engineered surface roughness to a digital plate during

the lamination process, as well as having the same unique LUX

dot shape and 1:1 imaging capability.

LUX Membrane 200 adds an engineered surface roughness to the plate, along with the high fidelity imaging

inherent in the LUX process

The surface texture imparted has a roughness of about 400 nm,

very similar to that of MacDermid capped digital plates such as

Digital Epic and Digital MCH. In these capped plates, this

roughness frequency had been proven over thousands of

kilometers of printing to deliver improved solid ink density (SID)

and reduced mottle, so we targeted this same roughness for our

LUX process as well. The surface pattern is present throughout

the tone range, improving the ink transfer of both dots and solids.

The surface pattern is random, and thus cannot create

interference patterns (e.g. moiré) with any other screening

elements used in the artwork.

LUX Membrane 200 adds a random surface pattern throughout the tone

range, to both solid and dot surfaces

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White paper l 31 January 2013 I LUX Membrane 200

The pattern has proven highly durable too, as it remains visible

on the plate surface even after 100,000+ meter print runs. This

ensures that solid ink density and gain remain consistent

throughout a print job.

LUX Membrane 200-treated dots before and after a 579,000 meter print run

Print Effects

On press, LUX Membrane 200-treated plates deliver significantly

higher SID and lower Mottle than either standard digital or LUX

Membrane 100-treated plates. And this improvement is

apparent on both solvent- or thermally-processed plates.

Solid Ink Density (SID) is improved significantly by the use of LUX Membrane 200

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While numbers quantify the effect well, they do not give one a full

appreciation of the impact that the improved print brings.

Visually, the effects of Membrane 200 are often quite striking.

LUX Membrane 200-treated plates give better ink laydown and color density on white polypropylene

Then benefits of LUX M200 are available on most substrates

from envelope stock to coated papers to polymeric films.

Mottle is decreased significantly by the use of LUX Membrane 200

SID is increased and mottle is decreased for Digital MAX imaged with LUX Membrane 200 (right) compared to Digital MAX imaged in standard digital format (left), both printed on paper.

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White paper l 31 January 2013 I LUX Membrane 200

Simplicity is a virtue

One of the nicest things about LUX Membrane 200 is its

simplicity. There is no extensive testing required to find the right

surface pattern and the digital imager can be run at its maximum

throughput because there is no need for fine details to be etched

into the solid portions of the mask.

Conclusions

LUX and Membrane 200 offer a combination of benefits no other

imaging technique can bring to package printers. The LUX dot

shape gives exceptional highlight dot stability, low mechanical

gain, and uniform dot height. LUX Membrane 200 imparts a

surface roughness to the plate that is durable, random, and

optimized to increase SID and reduce mottle in print.