Sublimation Ghosting BustingShahid Pasha
Ghosting mainly occurs in sublimation when the ink is still active even after you have opened the heat press as the transfer paper could have slightly moved during this process. When opening the heat press, the substrate and paper might move slightly resulting in the image to be slightly skewed from where it was intended to be pressed. This will leave a ghost-like image and ruin the blank. Unfortunately, there is no going back from this and you just have to start over.
Hopefully, these three ways of preventing ghosting from your sublimation production process can help save you time and money.
1. One of the great things about sublimation is the fact that you are not only limited to just one or two styles of products. You can make items from garments to cell phone cases, awards plaques to mouse pads, metal panels to beach towels, floor mats to blankets, and so on… you get the picture. The options are almost limitless. For each item, you need a little different pressure, temperature and time. One thing that many sublimators do when they get going too fast is change from one substrate to another without getting their time and pressure correct for the new item. They close the heat press or try to and then realize that they need to make an adjustment. Unfortunately, the ink has already started to activate and when you close the press the again, the transfer has slightly shifted. This will cause a ghost image and a ruined blank. The best way to eliminate this from happening is to slow down and plan ahead.
- Document all of your processes in detail so when you do need to switch from one substrate to another, the correct changes will occur for a successful press. Here is a great article from David Gross of Conde System about documenting your process.
- When switching substrates, make sure to prepress your item between two sheets of blow-out paper first to make sure the pressure is correct.
- Have everything you need laid out ahead of pressing from a blow-out paper to heat resistant foam and protective gloves.
2. Everything is set to press and your heat press is ready to go. At this point, make sure you have selected the best method for holding the sublimation transfer sheet to your substrate. Remember, this will depend on the type of substrate
- For soft goods, like garments, mousepads, bags and totes, make sure to use a specifically designed spray tack adhesive or a tacky sublimation transfer paper. Unfortunately, if you have small format equipment, at the writing of this blog, there is not a tacky paper available. You would have to have a wide format roll feed machine to be able to print on tacky paper. For small format printers, you want to take spray tack adhesive sold by your sublimation supplier, and spray a very fine mist on the transfer sheet. If you can see any of the adhesive puddling up on the sheet, then you were too close to the transfer sheet and sprayed too much. Check out my video / blog about using spray tack adhesive. The tacky paper and the spray tack adhesive helps to eliminate ghosting by keeping the transfer sheet stuck to your substrate even when the press opens up so the transfer sheet does not move while the inks are still active. With tacky paper, it is actually heat activated so it makes it easy to work with. I do not recommend using tacky paper or spray tack adhesive with hard surface items. The adhesive in both cases causes additional roughness to the transfer papers and therefore on a hard surface item that roughness will cause the ink to transfer with some graininess and you will not get as clean of a transfer.
- For hard surfaces, like photo panels, coffee mugs, serving trays, mobile device cases, it is best to use a special heat resistant tape. There are several types of heat tapes available with varieties of colors and thickness. You will need to find the one that you like the best for how you sublimate. Personally, I like a thinner tape that has some decent tack to it. When it comes to the color of the tape, you will find that everyone has an opinion, but I have talked to several of the tape manufacturers and they all say there is really no difference when it comes to the color of the tape as to how it works. Their claim is that the colors are just a chance in the pigment to the tape base and it plays no role in the adhesion of the tape. Now you will find people out there that swear by a certain color tape, but at the end of the day, the only factors should be the type of adhesive on the tape and the thickness of the tape base that works best for your process. After the selection of the tape, you will use the tape to lay out your projects, noting use a small amount of tape in two or three locations to hold the transfer in place during pressing. The tighter you can get the transfer to the substrate, the less likely you will have ghosting. You may even need to trim down your transfer sheet a little so the transfer sheet does not roll over the edge or do something else weird, as the paper heats up. Not only is the ink activating in the heat, but the paper is changing as the moisture leaves it and the tape is also fighting up because of the heat as well. Plan ahead for that!
3. The product has been pressed; time to get it off the press and take the transfer paper off without causing ghosting during this step. Be prepared to interact with the product immediately after the press is done by having some heat resistant gloves on and having a cooling area ready for the finished goods once they are done. Also, have your recycling bin nearby to clear out the used transfer paper when done so you can be ready for the next item. I recommend getting the transfer paper off as quickly as you can without rushing to eliminate opportunities for the transfer paper to move. In addition, when the paper begins to cool, some of the transfer paper coatings could stick to the substrate as well, so try not to set the item off to the side taking the paper off later. Personally, I am not a fan of the bucket of water to cool items, as the temperature needs to be just right or ceramics will start breaking and it just makes a big mess. I recommend having a concrete area nearby or some sort of a cooling slab of rock like granite or sandstone. Then once the product is done in the press, open the press gently but deliberately, so the item will not shift too much right away. Carefully move the product from the heat press over to your cooling area. Immediately remove the transfer carefully and deliberately so you do not lift the transfer off and then let it fall back on it. Try not to touch the imprinted surface too much as the polyester or polymer coating is still soft and malleable. Keep in mind, when you stretch fabric items, you can permanently change the fabric shape. For soft goods, you can just set those to the side to cool as the heat writing a paper will quickly dissipate. For hard goods, like ceramics, aluminum and hardboard, you will want to put them on a cooling surface like concrete which will suck the heat out of it. Place hardboard items face down so that way the natural warping that occurs during transfer will come out and flatten the items back down. Once the items cool to where you can safely handle it without gloves, the ink is no longer active and you can prepare it for delivery to the customer.
By following those three steps you should be able to almost eliminate ghosting from your production and be ready to deliver beautiful profitable jobs to your customers.