Have you observed yellow marks on the white t-shirt? Such discoloration can ruin the grace of fabric and sometimes imparts permanent tint.
You may have done all the right temperature and pressure settings to heat press but found a damaged shirt.
Yellowing on a white shirt occurs due to applying excessive temperature and pressure.
This is disheartening, but don’t worry. Some factors can cause the yellow color on white fabrics.
In this article, I will discuss factors in heat pressing which cause yellowing during heat press.
Additionally, in the end, you will find very useful tips to avoid yellow tints on white shirts by heat press.
Also Read: Most Common Sublimation Problems
Why Is My Heat Press Turning Shirts Yellow?
Here are some most important factors which cause the white shirt to turn yellow;
Excessive Pressure
Each substrate used in the heat press process requires special care during applying pressure. Some blanks need high pressure, while some give the best low or medium-pressure results.
Applying too much pressure on fabrics can cause the yellow color to damage the shirt.
Working at High Temperature
This is one of the most common reasons which can turn a white t-shirt into yellow.
For each of the blanks, there is a range of heat that a fabric can withstand.
for instance, the heat pressing temperature for polyester is 315oF to 350oF, and for silk is 270oF to 280oF.
If you exceed the higher limit, you will face a yellow issue on the fabric.
Moisture Residues
When you are going to heat press any fabric, do press it with an iron.
In this way, the moisture particle will be eliminated along with wrinkles.
If the fabric carries wetness, it can chemically react with the ink and transfer. You will observe a spark of the chemical reaction.
During this chemical reaction, moisture provides an oxidizing agent to the ink and vinyl. It results in yellow stains on the white shirt.
Moreover, moisture disintegrates optical brightening agents. The breaking up of such agents will allow yellow hues to appear on white t-shirts.
Poor Quality of Fabric
Various fabrics are available in the market; some have high quality, and some have low quality.
Low-quality fabrics cannot withstand even low temperatures and pressure. It is advised to buy high-quality fabric blanks to avoid yellowing problems.
Dirty Heat Platen
Keep the fabric and heat press platens free from dust particles.
There is a chance of previous fabric lint and vinyl fragment.
Residues of the previous batch on the platen can cause discoloring and staining of the white shirt.
Pay attention to the cleanliness and housekeeping of the heat pressing station for better-quality prints.
Read This: Sublimation Black is Looking Brown
How to Stop Heat Press from Yellowing?
Various ways prevent the heat press from yellowing the white shirts. Here are a few ways to follow and save the white fabric from discoloration.
Time and Temperature Settings
The time and temperature for heat pressing depend upon the nature of the substrate. Settings will be different for plastics, metals, and fabrics.
Stay stuck to the right settings if you are concerned about yellow stains. It is suggested to work using lower heat settings.
However, working at low temperatures doesn’t increase the duration. Extended time can damage the fabric.
Adjust the Pressure
Keep the pressure low when heat is pressing on white fabrics.
Applying appropriate pressure can prevent the yellow staining on a white shirt.
Keep an eye on the pressure gauge of the heat press.
Go from low to medium level depending upon the requirement.
Working with high pressure can burn the fabric and cause the yellow tint.
Use Teflon Sheet
Most beginners in the heat-pressing business need to remember to use protective papers. A protective paper can prevent heat from directly moving to the white substrate.
On the other hand, Teflon sheets are also a good replacement for protective papers.
Platens can move freely over such slippery sheets and don’t harm the fabric.
Due to their high strength, they can withstand high pressure and temperature.
Finally, you will get a white shirt without any damage or staining.
Clean Platen Regularly
Small lint and ink particles may attach to the platens, which need cleaning.
Alcohol or acetone-swabbed rags can easily remove such debris.
Clean the platens periodically to have tint-free fabrics.
If the platens are overused, replace them with new ones to have flawless heat pressing.
Let Suitable Cooling
Let the white fabric cool to room temperature after the heat-pressing process.
Proper cooling stabilized the fabric design, and ink formed a strong bond with the substrate.
Then peel off the protective sheet and transfer paper to avoid distortion in design color.
Related: Sublimation on color shirts
Final Words
Finally, when the heat press produces a yellow tint on white shirts, you have to control temperature and pressure settings. Also, let the fabric properly cool to room temperature.
By following these simple tips, you can prevent discoloration on white fabric.
Frequently Asked Questions (FAQs)
Why is my heat press turning my shirts yellow?
Most probably, you are applying too much pressure with high-temperature settings.
When you see a shirt begin to discolor, the heat and pressure are most likely too high.
How do you get rid of yellow with a heat press?
Take a small spray bottle of 100ml and mix 50% water with 50% hydrogen peroxide. Apply on yellow stains and cover with parchment paper. Press it for 10-15 seconds; the result is amazing. The white shirt is free from yellow tints.
Why is heat press discoloring white shirts?
A common reason is the presence of moisture particles in the fabric. During heat pressing, it turns to steam causing discoloration.