Like any good article on sublimation, it is important to cover the fundamentals of how sublimation works in the first paragraphs to steer newcomers in this business in the right direction. In my 25 years of experience in the heat-transfer industry, I have heard it all, from people trying to heat apply photographs (literally photographs) onto mugs, to people buying mugs at Wal-Mart and trying to heat apply sublimation transfers to these un-coated products!
I have learned to not assume that people have an understanding for the sublimation process, so here it goes, before we dive into the good stuff. Sublimation by definition is transferring solid ink from a paper carrier to a given substrate by heating the ink with a heat-transfer machine to 385 to 400 degrees F. The heat-transfer process passes the ink into a gas form without going into a liquid state. Time, temperature and pressure are needed to transfer the sublimation image from the paper to the substrate.
For sublimation to work, the substrate to be imaged must have a polymer coating applied to the surface to accept the sublimation ink. When the substrate to be imaged reaches 385 to 400 degrees F, magic happens as the ink turns into a gas and penetrates the open pores of the polymer coating. When the substrate cools, the polymer coating cools and traps the image in the coating. For sublimating on garments, they must be polyester or a polyester blend. Recap: Use sublimation transfers, not actual photographs, and use polymer-coated mugs for sublimation, not common household mugs from Wal-Mart!
I began experimenting with sublimation heat transfers in the mid 1980’s, but at that time sublimation transfers were either screen printed onto paper or made via the offset press. Sublimation is not a new process as many people tend to think, but what is new is the introduction of digital inkjet technologies to print sublimation ink onto transfer paper. The Epson piezo print head has taken sublimation printing to mainstream America and created the opportunity for anyone to enter this market for a small outlay of capital.
Not everyone can purchase an offset press, but most people can afford a desktop inkjet printer! Sublimation printing on flat stock and textiles has been a common decorating process in our industry for decades, but not until recent years have we been able to stretch the boundaries and sublimate on so many assorted cylinder objects like mugs, steins, dog bowls and more.
To get started sublimating onto curved surfaces, you need to do your homework on what equipment is available, as well as other methods to sublimate on a curved surface like using mug wraps, custom cylinder wraps, and equipment like the Pictaflex by ICI Imagedata. There are more ways than one to sublimate onto cylinder and curved-shaped substrates, as an example sublimating onto mugs can be achieved by using a mug heat-transfer press for small quantities, or for large-volume mug production, a mug oven is your best solution. With a commercial conveyorized mug oven, it is easy to produce up to 300 mugs an hour. (See Figure A)
Start With The Art
It is important to size your transfer to the substrate that you are decorating, and the old rule “less is more” rings true to avoid crowding an area with graphics, making your design busy and hard to look at. You should be able to read text from 10 feet away for most graphics on plaques, mugs and tiles; always use a high-resolution image to allow for better image clarity after the heat-transferring process.
Since sublimation inks turn into a gas during the transfer process, this “gassing” of the ink can cause a slight blur to the image as the substrate cools when sublimating on hard substrates, so it is best to use high-resolution images to reduce this blurring effect. It is important to cool the heat-transferred substrate as quickly as possible to stop the ink from gassing and ghosting the non-image area of your product. With high-resolution images transferred onto hard substrates, a simple fan will be sufficient to cool your product; however, lower-resolution images may need to be cooled quickly in a bucket of lukewarm water.
The paper width is a big consideration when ganging wraparound transfers for wider cylinder prints, like for dog bowls or metal tins. A wide-format printer offers paper widths in the range from 24” to 44” widths and can be ideal for gang-printing transfers for wider sublimation cylinder applications. Most small desktop inkjet printers work well for printing sublimation transfers, and common print drivers or free drivers (supplied by sublimation ink manufacturers) are fine for these smaller-format printers, whereas high-production inkjet printers require special software and a RIP drive to operate the printer. (Raster Image Processor). (See Figure B, wide-format Mimaki sublimation printer)
It is important to color correct the image before you print the transfer; you can make manual color adjustments on your computer screen once you have gained the experience and have a feel for what colors need to be boosted and how to improve contrast in the design. Most software has automatic color correction adjustments, but the pros have their manual color correction tricks that really help make a design pop off the substrate!
Software For Dye Sublimation Printing
The secret to great sublimation images is in the software and how to use it. AJ Wood from Images in Tile offers the following recommendations regarding software for sublimation:
One of the best moves you can make in your dye sublimation workflow is to rely on a dedicated photo-editing software such as Adobe® Photoshop®. Unfortunately, many dye sub shops are an outgrowth from other industries such as engraving or vinyl cutting where vector programs like CorelDraw are the rule. Dye sublimation requires a different approach to maximize sales. It is imperative that your pictures pop, and since pictures are photos, using software that specializes in jazzing up your photos is a virtual no-brainer.
AJ also adds that the next best move you can make is to move away from CMYK and enter the world of RGB. Many users feel that since today’s inkjet printers use Cyan, Magenta, Yellow and Black (K) inks that they should be working with CMYK files. Using CMYK is a direct path to flat, lifeless images. There are uses for CMYK in dye sublimation, but not on photographic imagery, and any CMYK output requires a dedicated CMYK workflow.
Many dye sub users end up sending CMYK files through an RGB workflow without realizing that their files are being converted to RGB before reaching the printer. All graphic-software applications prepare CMYK files for traditional offset color printing, used to print things like your brochures and business cards. Although modern inkjets use CMYK colors, they lay the inks down in a way that achieves a far greater amount of colors (gamut) than is possible in offset press printing. In fact, even offset print shops are moving away from standard CMYK to other color models.
As a dye sublimation specialist, you should be using a dedicated RGB color space to take advantage of the extra colors available. In short, comparing the amount of color possible between CMYK and RGB is like choosing between a set of 16 crayons and a set of 64 crayons. What kid wouldn’t go for the 64-color set! (AJ Wood is a graphic artist employed by Images in Tile, Joplin MO.)
Printer And Ink Considerations
If you are a small operation and want to get started on a budget, the Epson C-88 desktop and Sawgrass ink cartridges are the perfect choices. This low-cost start-up will allow you to experiment and gain the knowledge you need to be successful in sublimation printing. For cylinder and mug transferring, an investment in a mug press or a few mug wraps will get you started.
If you decide to use a household oven for sublimating on mugs, I recommend buying an electric toaster oven and dedicating this oven to mug decoration only—not for heating food. The residue from sublimation inks should not be ingested. Always consult your ink supplier for MSDS sheets and safety information.
If you already have an existing customer base and you are selling a volume of product, I recommend that you start out with the larger Epson 1280 or the Epson 4800 and Sawgrass or ArTainium bulk ink systems. And for even larger-volume shops, the Epson 4800, Epson 7600 or the Mimaki JV22 are excellent choices for large-format sublimation transfer printing.
Tricks And Tips For Sublimating On Curved Surfaces
- When using mug wraps for sublimating on coffee mugs, tape your transfer to the mug with heat-resistant tape and choose a mug wrap that has a quick closing and quick release clasp. (See Figure C) If you are using a toaster oven or household oven, it takes 12 to 15 minutes at 380 to 400 degrees F for best results. Commercial mug ovens can produce up to 300 sublimated mugs per hour!
- For full-wrap sublimated designs on mugs, lightly wet the top and bottom of the transfer paper to allow the paper to conform to the edge of the mug and avoid a crease in the paper. (See Figure D)
- For cell phone covers and other small curved surfaces, machines like the Pictaflex by ICI Imagedata are great alternatives. For more information on the process, go to www.Pictaflex.com.
- When using a conveyorized oven, remember not all commercial conveyor ovens are created equal, and it is important to have convection air inside the oven chamber to distribute the heat to all sides of three-dimensional items. Because of this, not all textile conveyor ovens work for this application, due to low wattage and insufficient air flow. Also, for best results, the conveyor system needs to be equipped with a stainless steel belt. Remember that your products will be in the oven for up to 15 minutes at 400 degrees F., and fiber-type belts will have a shorter life span under these extreme heat and time conditions.
- As mentioned above on the equipment side of the process, not all blank goods are of equal quality as well! Buy only quality blank goods for sublimation, especially in the case of mugs and cylindrical objects. Some low-cost mugs may be cheaper, but are useless for sublimation if the surface is not flat. Low areas in the mug surface will not allow portions of the image to transfer properly.
Since there is a slight learning curve to sublimating on curved surfaces, take it slow and do your R & D work before you take orders for a volume of sublimated products. Our industry is maturing quickly, and there are many resources available in our industry to help you learn more about the sublimation process. Most suppliers of sublimation supplies and blank goods are an excellent source for you to get the training and knowledge to be successful. Stay ahead of the curve by learning the secrets to sublimating on the curve! Thanks for reading.