The Pretreatment is inevitable for white ink. Why? Being white for the human eye means that the surface of an object reflects every wavelength of visible rays. If you want to print a white image on a black T-shirt, you would have to cover the fibers with white ink.
|
|
The pretreatment layer makes a thin cohesive film (like the blue line in the image above) to prevent the white ink from sinking into the fibers.
 It is very important that the surface should be as flat as possible, to keep the white ink mask as smooth as possible. So be sure to use HEAT PRESS to cure pretreatment with "parchment" (Teflon® coated sheet), to make the surface flat, 180 C degrees or (356 F degrees) in 35 seconds with high pressure.
On the other hand, you do not have to give pressure in curing ink: high pressure may causes "ink explosion", especially with rich white ink under CMYK ink.
Sometimes your heat press won't show you the right temperature. Check the actual temperature with a thermometer if you feel that your print is not white like a test sample. Also keep the temperature of the heat press, it may drop by 10C (20 degrees F).
|
| Here is the list of necessary amount of pretreatment diluted by standard "weight-equal". When you apply manually, especially for the first time, check the weight of the garment until you are trained. |
| Size |
Amount of Pretreatment |
| Standard Platen 14x16 |
30 g |
| Youth Platen 10x12 |
16 g |
| Baby Platen |
8 g |
| Letter / A4 |
15 g |
| pocket size ( 10x10 cm ) |
3 g |
Apply "less" amount for lighter-colored T-shirts.
|
When you dilute Pretreatment, add Distilled Water, not just drinkable water, to keep the quality and safety.
Control the thickness of Pretreatment in diluting. The best balance is to mix "double weight" of Distilled Water and Pretreatment together and shake upside down gently. If you do not have a scale, refer to the following number.
The following image shows the relations between the thickness of Pretreatment and the advantage / disadvantage in operation.
Our recommendation is to dilute 1:2 "volume" ratio.
|
|
Manage by the print quality, the types of garment (pale/dark-colored, thinness, material, etc.), cost and your controllability.
For example, when the print condition is a little worse, e.g. print on Polyester-mixed garment like 50/50, then use a little thicker 1-1.5:1 Pretreatment. In other cases, dilute it for saving money.
 If you dilute much thinner than our indications, the diluted Pretreatment cannot be stable in stock.
Here are the lists of recommended mixture but again the best answer depends on the garment you are going to print. We recommend making a test before you print.
|
 Volume Raito = 1 : 2 |
|
 Weight Raito = 1 : 1 |
|
 Weight Raito = 1 : 2 |
|
 Volume Raito = 1 : 1 |
|
Use either a spray, or a roller, or pretreatment machine. A spray gun (ex. WAGNER CONTROL SPRAY) is quick and easy, but more waste and you need space to use it. A roller is available wherever you like, for sleeves, pockets, etc. and has less waste but takes time and needs some skills. To apply our pretreatment in the best way, be sure to use our recommended option.
|
Select the way you pretreat.
  or 
|
For mass production, a special pretreatment machine should be available, just ask your dealer or Brother for other solutions.
|
The temperature of the surface may be lower than the indication if you feel Pretreatment and Ink are not cured enough by the heat press. If you feel the white is not white enough, e.g. white ink sinks into the fiber rather than be fixed at the surface, check the temperature first, and then check the amount you applied.
|
| The edge of the heat press is really wet by steam. Do not wet the pretreated surface. If pretreated garment is wet again by water drains, the active principle will be washed away. You cannot recover those stains even if you pretreat again.
|
|
Sometimes a conveyor oven may be too hot and cause burns on "wet surfaces from steam" on part of the printed garment. Be aware of the temperature control.
| |
 Without or less pretreatment ... ? |
| Let's see what is happening with no pretreatment. CMYK ink likes to sink into the surface of fibers and is cured with heat (see the left image below). When white ink is printed just like CMYK ink, it will be like the right image: white ink sinks into the fiber and it never reflects enough light. Imagine a glass of milk that looks white, but a drop of milk on a black cloth never looks white, just a dirty stain.
|
  
|
| Seeing is believing. The following photos are the same print image with /and without pretreatment. You can tell which is which. See the left one, white ink will sink through the T-shirt fiber, even to the opposite side.
|
 
|
| You may fail to properly apply pretreatment when you use roller or spray. Then the print will be as follows. Missing the pretreatment causes missing white print. |
 
|
 Failure in pretreating Enlargement
|
| Multi-Layer Pretreatment |
If you want higher quality, try Multi-Layer pretreatment, to apply less,(a little more than a half) pretreatment and cure, then again pretreat and cure. Double-layer pretreatment is good for 100% cotton garment, 3-4 layers for cotton / polyester garment, e.g. 50/50. It might be better to use a roller for fine control. This process produces some thin but solid layers of Pretreatment on the surface of garment to block white ink from sinking in. It takes time but it works.
On the other hand, do not apply too much Pretreatment at one time, the temperature of heat press may drop suddenly.
|
Conclusion:
  Apply enough pretreatment evenly.
 Cure pretreatment as flat as possible.
 Try multi-layer for better print quality.
|
|
