How do I mirror a design before printing it on heat transfer paper for T-shirts?
Tick 'Flip horizontally' in the rotate and flip tool, leave the angle at 0, pick PNG as the save format and print the result. Many heat transfer papers go face down onto the fabric, so the design is reversed when pressed, and mirroring it first makes it come out right on the shirt. Not every paper works that way though, so read the instructions for the paper you bought first.
Do you need to mirror at all?
That is the key question before you print a whole batch. As a rule of thumb: if the paper goes printed side down onto the fabric and is pressed from the back, the design needs mirroring. If the paper is peeled and the design placed face up, as with some papers for dark fabrics, do not mirror it. The instructions on the paper's pack are the authority, not this article.
The easiest test: print the mirrored design on plain paper first and hold it up to a mirror. If the text reads correctly in the mirror, that is how it will look on the fabric after transfer from a face-down paper.
Steps
- Open the Image rotator and flipper tool and choose your design file.
- Tick only 'Flip horizontally (mirror left/right)', leaving the angle at 0 and the vertical flip off.
- Check in the preview that the text is now reversed, which is what you want here.
- Under 'Save as' choose PNG. If the original design is a JPEG, the result comes out as a PNG with no further loss.
- Download the file and print it at the size you need.
Why PNG in particular
- A flip moves pixels exactly as they are with no smoothing, and PNG stores them losslessly, so the design stays as sharp as you made it.
- If the design has a transparent background, the tool ticks 'Transparent background' automatically and PNG keeps the transparency. That matters if you will place the design on a colored print page or combine it with others.
- JPEG is re-compressed at quality 92 and can add faint smudges around sharp lettering, which show more on fabric than on screen.
Printing several designs on one sheet
Transfer paper is not cheap, so it pays to fit several small mirrored designs on one sheet. Mirror each design separately, since the tool handles one image at a time, then gather them into print-ready pages with Images to PDF, and check your printer's scaling settings so the designs are not shrunk.
Common questions
Will a vertical flip do?
No. A vertical flip turns the design upside down like a reflection in water. Heat transfer needs the horizontal flip.
Is the file's metadata removed when flipping?
Yes, EXIF data is dropped because the image is redrawn. It makes no difference to printing.
Should I mirror a design with no text?
If it is perfectly symmetrical you will see no difference, but mirror it anyway if the paper calls for it, since any asymmetric element will be reversed.