Information on protecting prints that will need to be used outdoors.

It is becoming more and more popular .... Making prints yourself to use outdoors. Unfortunately, there is a lot of confusion about this and I want to clarify some aspects with this article. I will touch ground with the do's and the dont's, what to look out for and what you might need. I will use stickers as my basis for this article because they are most used outdoors. The effect and method of protection is in general for prints. So this will also apply to photo prints, canvas, teslin paper, waterslide decals, rub-on decal etc. In short: for all prints that are used outside that have already been printed on water-resistant material.

What to look out for:

An important mistake that is often made is that it is thought that a sticker only needs to be water-resistant for outdoor use. In addition to water, the biggest enemy of your print is the UV-radiation that comes from (direct) sunlight. Water-proofing a print is not to hard and is actually a matter of applying any general water-resistant laminate. This laminate can be both a foil or a liquid laminate in the form of a fixative, acrylic clear coat or sometimes even water-based varnish.

UV-radiation what is it, what does it do?

UV-radiation is the radiation coming from (sun)light which make a person color brown, get burned but a person also needs it to make vitamins. The same radiation affect your prints because it breaks down the pigments and your print will fade. The most harmful UV-radiation is in direct and full sunlight, this is the fastest working and fade the print to pale the fastest. However, in the shade, on cloudy days, behind glass (inside) and even in artificial light, there is UV-radiation that discolour prints.
How fast a print is discolored depends on a number of factors:

 - The ink or toner
- How long the print is exposed
- How strong the (sun)light is

It is also difficult to predict in advance how long the lifetime of a print is before it will fade. The only one of these three factors that can be predicted in advance is the lifetime of ink or toner when it is not protected. Among these inks and toner fall 4 categories which are used the most, namely:

  - Dye-based ink - The most commonly used "standard" inkjet ink
- Pigment-based ink - The more professional ink used in many "High-End" photo printers
- Solvent ink - The ink used in professional Sign printers
- Toner - Which is used in Laser printers

Unprotected Dye ink lasts 3-7 weeks, pigment ink 3-6 months, solvent ink 5-8 months and toner 4-7 months. These are guidelines and the reality can vary greatly, due to the factors mentioned above. There is also a lot of variation between types/brands of ink, whereby third party/nameless substitutes often score poorly.

How to counteract fading:

UV protection or the ability to use outdoors, has nothing to do with the used media (the paper / foil). Of course, a media itself must be water-resistant or processed in such a way that it can withstand water. In the case of inkjet/solvent media, matte media give the best protection because the ink is already partly absorbed and thus better protected against influences. Fading a print is a fight between UV-radiation and the color pigments in the ink/toner that is used. Complete exclusion of fading is unfortunately not possible, the only thing you can do is slow down the effect. Even car paints, outdoor stains, boat paint, etc. which contain very strong pigments, will eventually fade.

Protecting your print is done with a protective film/laminate foil or a clear coat with UV blocking. These are usually described as UV-resistant, UV-resistant or UV-block. In the case of a clear coat, most paints suitable for outdoor use have some form of UV protection. At the time of writing, laminate films from PoliLux and clear varnish from Motip (art.nr 04000 or 04009) are available in the shop and offer UV protection.

What is the best and lasts the longest:

As indicated earlier, it is not possible to predict in advance how long a print will last with protection before it fades. The only way to find out is to place a print outside and wait until it fades. As a test, you can cover part of the print with silver foil on opaque black paper and place it over part of the print. Then, for example, you leave the print outside for a month in the full sun and then compare the covered with the bare part to see how large the difference is. Even then, the test result does not guarantee the durability of the next project due to the strength of the UV radiation on that moment. On a professional level, special test setups are used, where a very strong light source with a high amount of UV is shone on the test print. This will test how much and how long it takes for the print to fade and this is put into perspective on average daily impact.

In general, the use of a pigment ink or a laser printer is the most suitable and accessible/affordable. As protection, both a (PoliLux) laminate film or (Motip) clear coat has good protection, each with its own advantages. With clear varnish you can determine the thickness yourself and the thicker the lacquer layer the higher the protection. A laminate foil is easier to apply without "hassle". In contrast to clear coat, a film provides a more stable protection because its thickness is always the same.

Matte finish gives better protection than a glossy one. This is because a matte finish is just a bit less clear and this will block part of the light. With matt finish, I aim at the clear coat or laminate film, but without finishing, a matte media will last a little longer. Especially with inkjet media, this can give a significant difference because the inks are absorbed into the mat layer and thereby receive better protection against influences (UV, moisture and dirt). An additional advantage of a matte result is that the print is more visible, because less glare takes place.