September 14, 2018
By Jimmy Lamb
Anyone who has worked with dye sublimation for the production of soft signage is familiar with stories of trouble managing colours effectively, reducing downtime, and preventing clogged nozzles and broken printheads. Fortunately, the sources of all of these issues can be addressed with the following tips, tricks, and techniques.
Managing the colour output of a dye sublimation printer can be challenging because a number of different factors come into play when working with both ‘digital’ colours and sublimation inks.
First, the graphics as seen on a computer monitor must be converted from a red, green, and blue (RGB) colour space to cyan, magenta, yellow, and key/black (CMYK), so the printer can recreate them accurately. A specific RGB profile or custom print driver will need to be activated, unless working with a raster image processor (RIP), which will use CMYK.
Whether using an International Color Consortium (ICC) profile or a custom print driver, it is a good idea to create a colour chart. This involves printing out and sublimating an entire palette of colours on a pure white substrate. The result is a visual reference for both in-house staff and customers, allowing them to choose the proper colours for images prior to printing. Thus, even if these colours do not look the same on a computer screen as they do on the soft substrate, the chart helps ensure the output will achieve the desired colour match every time.
With that in mind, consistency is key. Colour management software allows users to make selections based not only on colour mode, but also type of transfer paper and soft substrate. Any change in these variables, throughout the production process, will affect the final output.
Given such variables also include pressing time, temperature, and pressure, it is necessary to experiment and test until the desired results are obtained. Then, the shop can establish a set of standards with which to continue to work—with the understanding any change in these standards can lead to changes in the appearance and quality of the final product.
Another negative variable is hidden moisture, which does not come out from sublimation papers and substrates until the heat press is closed. This moisture can cause colour shifting, image bleeding, and the uneven transfer of solid-filled areas in a graphic. To minimize these unwanted effects, the transfer paper should be kept in a sealed, plastic container or stored in another cool, dry place. Soft substrates can also be ‘pre-pressed’ to release hidden moisture before the transfer paper is affixed.
Time is certainly money in the dye sublimation industry. The more products that can be created within a given amount of time, the greater the profits. The ability to reduce downtime—i.e. when the heat press is left idle—is a critically important part of optimizing productivity.
Sometimes, all it takes is a little reorganization and rearrangement of the production workspace to improve efficiency and keep the line running smoothly. First, a staging area should be stocked with heat tape, scissors, and other essential items, so as to reduce the amount of time it will take to affix transfer papers to substrates. Next, a cooling area should be designated, where transfers can be quickly removed and finished graphics allowed to properly decrease in temperature.
It is also important to set aside space for a packing area, stocked with prepared boxes and a postage meter. If signmakers spend less time on shipping, they can spend more time selling, printing, and pressing.
While the aforementioned ‘trial and error’ of experimentation and testing are always a reality with dye sublimation, there are ways to reduce waste. For one thing, pressed substrates should not be stacked until they are completely cool; otherwise, they can transfer their colours to each other. Similarly, the removal of transfer paper from a substrate should be quick and even, immediately after the substrate leaves the heat press, to prevent ‘ghosting.’
It is also important with fabrics to use a lint roller to remove any dust and stray fibres before applying the transfer paper. This will help prevent little blue speckles from showing up on the finished material.
Finally, images should always be printed about 6.4 mm (0.25 in.) larger than the size of the substrate, providing a margin of error when aligning everything.
Preventing clogged nozzles and broken printheads
The composition of the ink used in dye sublimation can have a major effect on colour accuracy, production speed, and print quality—and even on the length of the equipment’s useful life.
Sublimation inks must be formulated with a specific printer in mind. Indeed, not every inkjet printer used in the sign industry can process sublimation inks. Some of their printheads apply heat, which can cause premature gassing of the ink’s dye solids. Less expensive bulk inks can introduce air bubbles and contaminants into the printer, leading to irreparable damage to the hardware.
As such, caution should be taken when purchasing bulk inks in order to ensure the printer performs as desired and preventing breakdowns and/or damage.
Jimmy Lamb is manager of education for Sawgrass, which integrates printing hardware, software, and inks for dye sublimation product decorating. For more information, visit www.sawgrassink.com.
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