How to Clean Image Edges Before DTF Printing

Cleaning image edges: white edges, grey edges, unwanted edges

Clean Image Edges | Image Preparation | For LINKO DTF printers | Windows and the English interface of Adobe Photoshop

1. What this document covers

In DTF printing, a white edge, a grey edge, stray color, or a rough edge around the design affects the finished print. The cause can be the image itself. The printer outputs the pixels in the image as they are, including the ring of leftover pixels you cannot see on a white canvas.

This document shows how to clean the background and the edges in Adobe Photoshop before printing, so the problem is removed at the source.

1.1 Find your situation and go straight to the section

Match your situation in the table below, then go straight to the section named. You can skip the sections before it.

What you see in the image	What it becomes in the printed result	Go to
Background not fully removed, leftover background color at the edge	A ring of stray color around the design. Light leftovers show clearly on dark fabric.	5.1 Remove leftover background
White edge, grey edge, or stray color	A white outline appears around the design. It is very visible on dark fabric.	5.2 Remove white and grey edges
Unwanted semi-transparent edge	The edge can look grey, show the fabric through, or give an uneven white ink outline.	5.3 Remove semi-transparent edges
Rough edge, jagged edge, unnatural edge	A jagged original affects the printed edge. Do not try to compensate with print settings.	5.4 Rough and jagged edges

1.2 What this document does not cover

Edge cleaning removes background and edge problems only. It cannot restore sharpness, pixels, or detail that the original image has already lost. The following are out of scope:

The original image has too low a resolution, or is already blurred. Replace the original; Photoshop cannot recover it.
Print color does not match the screen. This is a color-management issue.
White ink choke, ink amount, and other RIP software settings. These are print settings.

1.3 Before you start

File format: PNG, PSD, or TIFF with a transparency channel. JPG has no transparency, so remove the background first using chapter 3.
Color mode: an RGB image can be used directly. See Check Print-Ready Images section 2.4 on whether to convert.
Resolution: calculate from the actual print size. 300 PPI or above is recommended. See Check Print-Ready Images section 2.2.
Software: Adobe Photoshop CC 2018 or later.

1.4 The workflow

Open the image → remove the background → check the edges → clean the edges → confirm the result → save and export

2. Open the image

Open Adobe Photoshop.
Click File → Open.
Select the image you want to work on and open it.

Note: If the PNG already has a transparent background, the canvas shows a grey-and-white checkerboard. Go directly to chapter 4 to check the edges. Chapter 3 is not needed. Using the Magic Wand Tool on a transparent image can easily select the wrong area.

3. Remove the background

If the image has a background that should not print, or leftover background pixels, remove the background first and keep only the design. Choose a method below according to how complex the image is.

Why this matters for DTF: Every pixel that is not transparent is printed. A light leftover can be almost invisible on a white canvas. On dark fabric it becomes clearly visible, as a ring of stray color around the design.

3.1 Remove the background with the Magic Wand Tool

Use this method when the background is one color and contrasts clearly with the design.

Select the Magic Wand Tool.
In the options bar, set Tolerance to a starting value of 20 to 32. Select Anti-alias and Contiguous.
Click the background area you want to remove. A dashed selection outline around the area means it is selected.
If part of the background is not selected, hold Shift and click the remaining areas. Repeat until the whole background is selected.
Right-click and select Select Inverse. The selection now covers the design instead.
Press Ctrl + J to copy the design to a new layer.

Note: A tolerance set too low leaves background pixels behind. A tolerance set too high takes part of the design with it and leaves gaps. If a click selects clearly the wrong area, press Ctrl + D to deselect, change the tolerance, and click again.

3.2 Handle complex areas with the Pen Tool

When the Magic Wand Tool cannot select the background accurately, use the Pen Tool to trace the edge of the design by hand. This applies when the background color is close to the design, or when the background is a gradient.

Select the Pen Tool.
Click point by point along the edge of the design. Keep the path tight against the edge, and close the path so that it surrounds the whole design.
With the path closed, right-click and select Make Selection.
In the Make Selection window, set Feather Radius to 0 px, select Anti-aliased, then click OK.

Important: Do not keep the settings that happen to be there. If feathering was used earlier, “Feather Radius” may not be 0. A feathered selection produces a soft semi-transparent edge, which is the problem this document removes. Confirm both values every time.

Press Ctrl + J to copy the design to a new layer.

3.3 Hide the background layer

After the design is copied, click the eye icon in front of the original background layer in the Layers panel. The background layer is hidden, and only the design remains.

4. Check the edges

After the background is removed, check the edges. On the default transparent checkerboard or on a white background, white and light leftovers at the edge are almost invisible. Add a contrast background to find them.

Click Create New Fill or Adjustment Layer at the bottom of the Layers panel .
Select Solid Color.
Select a color that contrasts strongly with the design.
Drag the new solid color layer below the design layer.
Check the edges once on a light background and once on a dark background. A dark background reveals white edges and light leftovers. A light background reveals dark leftovers and stray edges.

Important: The solid color layer is a checking tool only. It is not part of the image. Delete it or hide it before you export in chapter 7. If you do not, the transparent background is filled with that color and the whole area prints as a solid block.

5. Clean the edges

Work from the result of chapter 4. Complete only the section that matches your situation, and skip the rest.

5.1 Remove leftover background

Hold Ctrl and click the layer thumbnail to load the design as a selection.
Confirm that the design layer is selected. It must not be the background layer or the solid color checking layer.
Click Select → Modify → Contract.
Enter the number of pixels to contract, then click OK.
Right-click and select Select Inverse. The selection now covers the edge area.
Press Delete to remove the leftover edge pixels.

Note: The contract value depends on the image resolution and is not a fixed number. Suggested starting values: 1 to 2 px at 300 PPI, and 2 to 4 px at 600 PPI. Too high a value eats into the design itself. Start low, check the result, and run the step again if it is not enough.

5.2 Remove white and grey edges

Why this matters for DTF: DTF prints the color layer first, then the white ink underbase beneath it. White pixels at the edge of the design are printed as part of the design. After pressing, they appear as a white outline around the design, which is very visible on dark fabric.

Select the design layer in the Layers panel.
Click Layer → Matting → Defringe.
Enter the width to process. Suggested starting values: 1 to 2 px at 300 PPI, and 2 to 4 px at 600 PPI. Then click OK.

If leftovers remain after one pass, run the step once more, or use the contract-and-delete method in section 5.1 instead.

5.3 Remove semi-transparent edges

Why this matters for DTF: Unwanted semi-transparent pixels can make the edge look grey. They can also let the fabric show through, or give an uneven white ink outline. After cleaning, check the edge again in the white ink channel preview in the RIP software (PrintFactory).

Use the steps in 5.1 Remove leftover background: load the selection, contract, invert, and delete. This cuts away the semi-transparent transition pixels and leaves a clean solid edge.

If the unwanted edge is clearly white or clearly black, you can also try Layer → Matting → Remove White Matting or Remove Black Matting first.

Note: A soft transition that belongs to the design, such as hair, smoke, or a shadow gradient, is not an unwanted edge. Do not process it with the methods above, because that damages the design. For such designs, print a small test first.

5.4 Rough and jagged edges

Why this matters for DTF: Rough or jagged edges already present in the original image affect the printed edge. They become more visible when the print is enlarged. Replace the original with a higher-quality file. Do not try to compensate with print settings.

A rough or jagged edge means the original has too low a resolution, or has been compressed repeatedly. Get a sharper original. Photoshop cannot restore detail that the image has already lost.

6. Confirm the result

After cleaning the edges, check once more with the dark and light background method in chapter 4. Confirm each item:

The background is fully removed, and only the design remains
The design is complete, and the contract step has not eaten into the detail at the edge
On a dark background: no white edge, grey edge, or light leftover
On a light background: no dark leftover and no stray color
No unwanted semi-transparent edge

If any item fails, return to the matching section in chapter 5 and process it again.

7. Save and export

Important: Delete or hide the solid color checking layer created in chapter 4 before you export. If you export with it in place, the transparent background is filled with that color and the whole area prints as a solid block. This is the step most often missed, and the one most likely to scrap a whole batch.

7.1 Before exporting

Delete or hide the solid color checking layer from chapter 4, and every layer that should not print.
Confirm that every layer that should print is visible.
Confirm that the canvas background shows the grey-and-white checkerboard, which means it is transparent.
Confirm that the image size matches the target print size.

7.2 Export the PNG

Click File → Export → Export As…
In the Export As window, set Format to PNG, and confirm that Transparency is selected.
- Do not select “Smaller File (8-bit)”: the number of colors drops to 256, which can affect gradients and semi-transparent edges.
- Do not select JPG: JPG is not a print delivery format for LINKO DTF, and it has no transparency support.
Click Export, choose the save location, enter a file name, then click Export again.
Save a PSD source file as well. It keeps the layers for later edits.

7.3 After exporting

Open the exported PNG again and confirm:

The background is transparent, shown as a grey-and-white checkerboard
The design is complete and not cropped
The size matches the target print size
No new problem has appeared at the edges
The solid color checking layer has not been exported by mistake

After importing into the RIP software (PrintFactory), open the white ink channel preview. Confirm that the white ink outline aligns with the edges of the color design and does not spread beyond it. This finds leftover edge problems before printing, and saves film and time.

White ink settings: Set White Ink Usage and Set White Layer Choking

After exporting, return to Check Print-Ready Images chapter 3 and check the image again. Print through the RIP software (PrintFactory) only after it passes.

8. Frequently asked questions

Q: There is a white edge on the print. Is the printer faulty?

A: Not necessarily. Use the method in chapter 4 first: place the design on a dark background and check. If a white line appears at the edge, the cause is the image, so handle it with chapter 5. Is the edge in the image clean but a white edge still appears? Check the white layer choke setting in the RIP software (PrintFactory). If that does not help, contact technical support.

Q: The image looks fine on the computer, but the printed edge looks grey and rough. Why?

A: A computer screen blends semi-transparent pixels with the white background, so the transition looks soft. On the printed result, those semi-transparent edges can look grey, let the fabric show through, or give an uneven white ink outline. Handle this in the image. See section 5.3.

Q: What contract value should I use?

A: It depends on the image resolution and is not a fixed number. Suggested starting values: 1 to 2 px at 300 PPI, and 2 to 4 px at 600 PPI. Too high a value eats into the design itself. Start low and increase it if the result is not enough.

Q: Can I print an image cut out with a phone app or an online background remover?

A: This is not recommended. Images exported by such tools can carry compression, semi-transparent edges, or too low a resolution. Check the image with chapter 4 first, then decide whether cleaning is needed.

Q: The design has shadows, hair, or a gradient at the edge. Should those be cleaned too?

A: Do not process them with the contract or Defringe methods in this document, because that damages the design. These are intentional semi-transparent transitions. Confirm the print result at the design stage, and print a small test first if needed.

Q: How do I tell quickly whether the cause is the image or the equipment?

A: When there is a white line or stray color at the edge, check the image edges with this document first. When colors overall are not deep enough or look grey, work through Troubleshoot Print Color Differences layer by layer. Banding across the print is an equipment-side problem, so contact technical support.

9. Related Documents

After cleaning the image edges, return to Check Print-Ready Images chapter 3. Check the image again. Continue to printing in RIP Software (PrintFactory) only after it passes.

9.1 Image Preparation

Check Print-Ready Images— Entry document for this set. The 7 checks before printing, including the pixel-to-size table.
Fix Dull or Grey Blacks— Black areas that print grey or not dark enough.
Troubleshoot Print Color Differences— Layer-by-layer troubleshooting for incorrect print colors.
Why Print Colors Differ from Screen— Differences between the screen and the printed result.

9.2 RIP Software (PrintFactory) Settings

RIP File Processing & Output Workflow— File processing and output workflow.
Set White Ink Usage, Set White Undercoat Method, Set White Layer Choking
Adjust Layout and Size— Size, copies, spacing, auto nesting, manual positioning and mirror printing.
Select ICC Profile— Select the color profile.

LINKO Technical Support
Email: support@dtflinko.com
Website: www.dtflinko.com