The white printed layer is provided to back up the design layers and render them visible from the design side of the panel. Total opacity in this layer is not a requirement, it must though be sufficient to block to an acceptable extent, the subsequently applied black layer from showing through it. Test print to find the lower of the acceptable ink limits (invariably less than 100%) and assess the result in exterior lighting conditions with dark subject matter behind the print and visible through its perforations. Results will be deceptive if the test print is viewed in lighting conditions that do not reflect those the print will encounter in daylight.
The black layer is provided so as to absorb light and present a clear view through the applied graphic. In practice, this can be accomplished with a very light weight of pure K black printed as a flood coat. Again, aim for the minimum level of ink that accomplishes the desired result. A fully saturated flood coat is no more effective in functional terms than a lighter coat and the additional ink it uses may contribute to the potential for hole blocking.
In general we recommend initiating a faster or more aggressive curing condition so that ink jetted into perforation voids is cured or pinned before it can accumulate at the perforations’ edges (which can lead to the film not adhering to the glass fully). This will also mitigate the possibility of it forming hardened rings as it will remain on the liner surface away from the perforation boundaries.
We further recommend that prints are nested on the material to avoid, if possible, the lamps sitting over and heating up the edge of the material when changing print direction which may cause curling of the edge of the material.
The print should be evaluated in conditions typical of those it will meet in use. Evaluate the design side of the print in daylight conditions with something darker behind the print. Evaluate the other side of the print by viewing from within an interior space to daylight beyond. From the print side, an acceptably colored image should be seen with clean highlight and no detail in fully saturated shadow. From the other side, no print detail should be seen other than a faint ghosting caused by the accumulation of ink on the edges of hole.
Test printing must be undertaken to ensure that amount of ink used and/or the amount of curing does not block the holes in the perforated window film, and/or reduce the strength of the adhesive – a test application onto a window is essential. You can find additional clarity around printing terms in our glossary. When you are ready to carry out a test application, remove the liner and test the sample by dragging it over the surface of a window or glass sample to check the adhesive contact between the glass and the film:
a) If the object slides freely over the exposed adhesive, it is likely the graphic is exhibiting symptoms that could cause the film not to adhere to the glass fully, or
b) If efforts to slide the object as detailed meets resistance preventing its movement, the graphic should apply normally and adhere reliably.
Please leave the print to fully cure before removing the liner.
It is not possible for us to test all combinations of artwork, RIP settings, press model, press settings, age of the lamps, and ink types.
An alternative production method is to print the image layer with an inkjet printer (UV-cure, solvent, ‘eco-solvent’ or latex) and then screenprint the white and black layers.
There may be minor variations in the perforating dimensions across the width of a roll of perforated window film. These differences are in the main invisible, except sometimes when butting together clear perforated material* (particularly with the smaller holes of Performance HD) printed with multiple layers of ink. So, whenever two or more pieces of the same clear perforated window film are used next to one another, they should be matched to provide a uniform appearance.
Material from a single roll or batch must be used on a single graphic. In general, clear perforated window film from a roll must be matched as shown in the figure below. The dark line represents one edge of the film.
The matching edges are always rotated to meet each other. Panels 1 and 2 are a matched set. Pieces 1, 2 and 3 are matched, etc. By following this method you can match as many sheets from a roll as are required for any installation.
* = this method also applies to Translucent White perforated window film
The above information is intended as a source of information, is given without guarantee, and does not constitute a warranty.
Purchasers should independently determine, prior to use, the suitability of the product for their specific intended purpose.