Affects Version/s: Only available from nS Delta 10.0.X.
When we start Calibration Wizard and we set up the inks, we can configure different White Inks on Custom Inks Setup, by selecting this ink on the right printing head and clicking on the White button on the right, which will open the Settings menu.
The option we use for white inks is:
- Flat (formerly Dark and Colored Media in nS9) covers all the opaque parts of the image in white ink. If the image has a transparent background, the program will detect it. Supported: PSD, TIF, and PNG files. Not supported: JPG and PDF.
WHITE INK - FLAT
In every part of the image that has the background, we have a white layer.
DTF printing and preparation process
The process for printing on DTF is elaborate but similar to the process on DTG with some differences. The standard process is as follows:
- We cut and set the film on the printer table. Depending on the film we might require to use tape for it to not get curly. Be sure to print on the correct side of the film (for the films tested this was the outer side).
- Print on the film. After printing, depending on the amount of ink, ink can be quite liquid, so we have to move it carefully.
- Take the film to the drying press and let it dry at 160c for the 30s. This will help the ink to stabilize and cover more homogeneously. This drying press should not touch the ink, and stay a few cm from the ink.
- Add the glue powder to the printed areas of the film. The needed amount of powder will stick to the ink on the film.
- Take the film back to the dryer and leave it at 120s at 160c.
- Set the t-shirt on the press and put the film over it with the ink in contact with the t-shirt. Press it for 10s at 140c.
- Take the T-shirt out and press it with your hand moving it until the film feels cold. Once it's cold we can pull from a corner and carefully take the film out. The ink should be completely dry and fixed to the fabric, we can touch it with the finger to get sure. If the ink is not fully fixed we might need to increase any of the process timings.
- For a less plastic feeling, it's recommended to press again the t-shirt at 140c for 5s. Be aware this 2nd press might change the final colors, so if we use it, we should use it during the calibration process.
- After the process is finished we might find some humidity over the printed areas. Before reading with a spectrophotometer we recommend drying the printed areas.
Cutting White Ink
In order to achieve good printing results, it's needed to test the amount of white ink needed. An excess of white ink will generate an uneven white surface with areas completely white and areas with black dots. Not enough white ink will not cover the black t-shirt completely and then the white and other colors will not be intense enough.
The way to calibrate the white background is as follows:
- For the white testing, we will select a resolution and ink mode, with 5 inks in CMYK->W in neoStampa. We select a color mode that prints CMYK first, and then white over it. Then save the scheme.
- Then we will select a white square and print it. After that, on the same piece of film, we will copy and paste the square in another position, delete the old square, modify the amount of white ink (pre-cut) and set it to 90%, save the scheme, and print again. We will repeat the process up to 60%, depending on the results and amount of ink.
- Once we have all the squares printed we will continue to prepare the printing and press it to the fabric.
- We will look for the even, homogenous white square and set the corresponding white ink pre-cut on the scheme. Be aware that the time needed to draw and print each square might affect the final percentage we will use.
- If our whites look good at 70-80% of white ink, we will proceed to print the total ink limit test separately in both ink cuts to finally decide which one gives better results closer to the production way. If needed we will modify the white ink pre-cut at this point and save the scheme. We can then continue with the calibration from Calibration Wizard.
Calibrating a DTF printer
The process of calibrating a DTF printer is similar to a default calibration but has several key differences. To properly calibrate the material and the white ink, we have to print on special film, apply glue powder and press it into the black fabric.
- We start a Calibration and on Color Mode we select a 5-color or 6-color print, depending on if we want different properties on the second layer of white ink.
- We open Custom Ink Setup (three-point icon on Color Mode) and we set White ink as Flat.
- We set Total Ink Limit (Step 1) and Ink Cuts (Step 2) normally.
- Usually, Re-Linearization (Step 3) is unneeded, so we can skip it.
- In Black Generation, we will use GCR where we will find two different presets:
- DTG-HQ will have high usage on the white ink mask (reduces dithering)
- DTG-Eco will have a lower usage on the white ink mask (reduces consumption)
- We'll use a Medium sized target, RGB 180x3 T-SHIRT, which is developed specifically for DTG and DTF. Since it has already 3 copies of each sample embedded, we only need to read it once.
- This calibration only works with black T-shirts, so we have to create a new one for other colored substrates. We can just duplicate this calibration and re-use the linearization.
- On Custom Ink Setup we set White ink as Flat.
- We use the same data for Total Ink Limit (Step 1) and Ink Cuts (Step 2) and skip Re-Linearization (Step 3) again.
- On Black Generation, we'll set it as Black Only or GCR and print the black chart (BlackAdd_DTG) to see and select the desired black. Input the CMYK values from the black selected in the Rich Black field.
- We print and measure the RGB 180x3 T-SHIRT, and we finish the calibration.
- Depending on our workflow, we can create additional calibration/s with different settings on Custom Ink Setup:
- Off if we only want to work with white as a direct ink substitution.
- Copy from the extra channel if we want to use an alpha channel as white ink (first alpha for first white ink, second alpha for second ink, etc.)