5 the most fast. The most important one is: most folks can’t afford to wait a year to see if the printed job will fade. Avoid too-thin ink films. Materials not only have to remain 'lightfast', but they must also be “darkfast’. ∆E* means the difference between the original and the new…. Lightening of an ink diminishes its light fastness. With this in mind, ink manufacturers have to judge the effect of light on substrates using their inks by simulating lighting conditions. Car colors do, indeed, fade – but you do not notice it since you never have a brand new version of your car next to your older one! Washfastness is judged on a scale of 1 to 5, where 5 is most resistant to washing out. Water fastness of the inks was assessed with the print on natural paper according to the procedures indicated by ISO 2836. The part of a molecule responsible for its color is called the chromophore. 1 indicating the least fast and no. It is necessary to check and assign individual standards for every brand color since fading shifts are unique to each pigment combination. Photodegradation : It is all about the chemical makeup of an object. tetrachlorethylene, respectively. It’s like “sunscreen” for inks. Congratulations to artist Sophie Epperlein, our latest Instagram winner! How important is it for the work produced by the printer? Size of the samples: 5×2 cm. Some samples from cheaply manufactured epoxy resins will even yellow in the dark! Pastel and tint shades also are more vulnerable to fading. The test pieces were exposed to the light at the same time as a sample blue wool scale consisting of a range of 8 blue dyes the light fastnesses of which are regularly graduated. Change ), You are commenting using your Twitter account. Limited Lightfast Some packaging can see short duration outdoor exposure of less than 30 days. Posted on 23 Nov 14:15, Give the Gift of Creativity! Interaction between the substrate and the ink – one thing that comes to mind here is that the more reflective the substrate, the bigger the UV “hit” the pigments in the ink are going to take in a given period of time. Its quite interesting to know in depth about light-fastness. In these inks, it is generally acceptable to use the most fugitive pigments such as fluorescents, rhodamine, and methyl violet. Obviously, light fastness is more critical than the other criteria looked at here, as printed material is more likely to suffer from light exposure than the other phenomena tested. Solvent fastness was assessed on the print on natural paper according to the procedures indicated by ISO 2837. The colour fastness of each ink was evaluated after irradiation, both before and after an ageing treatment. They provide the best method for assessing the accelerated light aging of products such as pigments, dyes and inks, which are sensitive to the long-wave and visible wavelengths of sunlight. No 1 indicates the least fast and no. a highly wood-containing substrate of low light fastness will soon yellow and it would be of little benefit to print on it with a blue ink of maximum light fastness. The energy radiated via the electromagnetic spectrum is not uniformly distributed throughout the world. The same printed surface could also react to Chemical Attack from solvents that come into contact with the print from overprint lacquers, varnishes, lamination adhesives or even leaching of chemicals from the materials stored in the package. ( Log Out / Water can come into contact with printed matter but almost exclusively as a result of accidental or extraordinary events, such as floods. There are light absorbing color bodies called chromophores that are present in dyes. Checking colour fastness of the ink samples on coated paper was considered more critical and rigorous, since this kind of paper allows the application of a thinner and therefore, more sensitive ink film. So garme... F abric Testing: Fabric is the most important raw material for garments. It will very substantially depending on the substrate to be printed and the printing forme. Where possible utilize a protective overprint varnish with weather ability properties and blocking agents with ability to screen out UV light in the suns spectrum. There is no way to bring back a faded package. We have to run our ink on the press, under normal commercial conditions, and that is the final test.When the ink does go on the printing press, the press runs are the final proof of whether the ink manufacturer has successfully completed their work. ( Log Out / Optimally, the customer wants to choose the most inexpensive pigment with adequate of fade resistance to meet established end use specifications. Light fastness is the term used to describe how resistant to fading an item is when exposed to light. Located just outside the daylight band, these wavelengths are more energetic and are largely responsible for color fading. Double check for any additional requirements regarding chemicals that prints are subject to come in contact and the ink/coatings ability to withstand that environment. For this reason alone the decision maker should consider which light fastness is really required for a specific printing job. Photo- Oxidation : Photochemical oxidation : The Colourant molecule gets exited under oxidation process . After the first 3 months there were no visible signs of fading. Adding around 90% of Transparent White or Opaque White to a mixture reduces the light fastness by 2 points. The plant, which is a pool type irradiation facility, uses a radio isotope source of Co-60 having a maximum nominal activity of 3.7 x 1015 Bq (100,000 Ci). You can apply a clear UV cured topcoat on our inks if you need extreme fade resistance. Furthermore, if the colour darkens, the letter N is added to the index. Fortunately, there are well-established protocols to avoid fading problems based on end-use exposure. It incurs around 70% of the garment cost and nearly 100% of the ex... Tensile Properties of Yarn: A yarn’s tensile property can be defined as the maximum force/load that is required to break the material. Atmospheric pollution: which can cause rapid deterioration. The light fastness of prints refers to a print‘s resistance to light exposure without direct exposure to the weather. What do the different degrees of light fastness mean? Basic principles for calculating the light fastness of mixtures. Influence of any topcoats also used – this is very important. The light-fastness is indicated on each as follows: *** = Maximum light-fastness = 7 ,8 Blue Wool Scale ** = Very good light-fastness = 5, 6 Blue Wool Scale * = Good light-fastness = 3, 4 Blue Wool Scale Generally, it can be stated that the changes in colour of the printed material (paper + ink) due to the combined treatment of irradiation and ageing were, exclusively or almost exclusively, the result of a darkening of the paper. Light fastness was assessed on the prints on coated paper according to the procedures indicated by ISO 2835 , using a Xenon lamp 150S Heraeus Xenotest with 1250 W/m2 high-pressure.