SEG fabric selection guide

How to Choose SEG Fabric for Backlit and Non-Lit Frames

Choose SEG fabric by the frame lighting first. Backlit frames need even light diffusion. Non-lit frames need a smooth, opaque print face. Blockout fabric is useful when rear light or background show-through must be stopped.

After that, check stretch direction, recovery, construction, heat shrinkage, silicone edge fit and the finished graphic inside the actual frame.

Compare SEG Fabric Rolls Request Fabric Samples

Unprinted SEG fabric rolls, finished backlit SEG frame and sewn silicone edge — Match the unprinted fabric roll to the lighting, printing, sewing and frame system.

3 typesbacklit, non-lit, blockout

2 directionsMD and CD behavior

1 real framefor final approval

7 checksbefore bulk order

Quick Answer: How Do You Choose SEG Fabric?

Decide whether the frame is backlit, non-lit or needs blockout.
Confirm direct dye sublimation, transfer sublimation, UV or latex compatibility.
Measure stretch and recovery in the machine direction and cross direction.
Compare woven and knitted construction for the required fit and finish.
Measure heat shrinkage under the real printing and heat settings.
Match the silicone or TPE edge to the exact aluminum profile.
Print, heat, sew and install a finished test panel before bulk production.

Backlit vs Non-Lit SEG Fabric

Lighting is the first selection decision. Do not use one fabric specification for every SEG frame.

Frame Type	Fabric Must Do	Main Test	Common Failure
Backlit SEG	Transmit and spread LED light while keeping color density	Install the printed sample in the actual illuminated box	Hotspots, pale color, pinholes or uneven white
Non-lit / frontlit SEG	Give a smooth matte face, good opacity and controlled tension	View under the real room or exhibition lighting	Glare, show-through, wrinkles or sag
Blockout SEG	Stop light and hide the wall, frame or old graphic behind it	Place the finished sample in front of the real background	Visible backing at cut edges, fold marks or weak opacity

Illuminated SEG lightbox using backlit polyester fabric

Backlit frame

Prioritize light diffusion, color density, white point and hotspot control.

Non-lit tension fabric display wall for an exhibition

Non-lit frame

Prioritize a smooth surface, opacity, low glare, tension and finished fit.

How Should Stretch and Size Recovery Be Checked?

SEG fabric needs enough stretch for a smooth face, but too much or uneven stretch can distort artwork and create weak corners. Test MD and CD separately because the two directions can behave differently.

1Mark
Draw a 500mm × 500mm square and mark the roll direction.

2Process
Print and heat the sample using the normal production settings.

3Finish
Cut, sew the real silicone edge and install it in the actual extrusion.

4Recover
Remove the panel, let it rest and measure the same marked points again.

Recovery error % = |rested dimension − original dimension| ÷ original dimension × 100

A lower result means the sample returned closer to its original marked size. Set the acceptable limit for your frame, artwork and replacement-graphic program.

Check horizontal and vertical artwork distortion.
Look for sag in the center and high stress at corners.
Repeat the test after folding and transport when graphics will be reused.
Do not approve a fabric from hand stretch alone.

Woven vs Knitted SEG Fabric

Construction is not a universal quality grade. Woven and knitted fabrics can both work when their printed, heat-set and sewn behavior matches the frame.

Construction	Useful Starting Behavior	Watch For	Best Approval Test
Woven	Often stable, crisp and controlled across large flat panels	Fraying, fold lines, limited forgiveness and corner stress	Finished panel with real cut and edge method
Knitted	Often more flexible, easy to tension and easier to pack	Uneven stretch, image distortion, sag and backlit pinholes if over-stretched	Installed sample with measured MD/CD tension

Simple rule: choose the behavior you can control in production. Do not choose knitted only because it stretches, or woven only because it feels stable.

How Much Shrinkage Allowance Should Be Used?

There is no safe universal allowance for every SEG fabric. Heat, time, pressure, ink load, paper, web tension and construction can all change the finished dimensions.

Shrinkage % = (dimension before heat − dimension after heat) ÷ dimension before heat × 100

Measure MD, CD and both diagonals before heat.
Print and heat with the real production recipe.
Cool the fabric before measuring the same marks.
Measure again after cutting and sewing.
Install the panel and record the final correction.

Keep shrinkage, installed stretch and sewing allowance as separate numbers. Combining them into one guessed percentage makes repeat orders harder to control. Use the free SEG fabric cut size calculator to keep these inputs separate and compare MD/CD roll directions before making the first finished sample.

How Do You Match the Silicone Keder Size?

The silicone edge is also called a gasket, bead or keder. Its size must match the exact aluminum groove. A silicone strip that works in one extrusion may be too loose or too hard to insert in another.

Input	Why It Matters	What to Record
Visible frame opening	Defines the required finished image area	Inside width, height and both diagonals
Extrusion groove	Controls insertion and holding force	Profile drawing, groove opening and depth
Silicone / TPE edge	Width, thickness and hardness affect the perimeter	Supplier, material, width, thickness and batch
Stitch line	Changes the effective finished graphic size	Distance from fabric edge, needle position and thread tension
Corner method	Extra layers can prevent full insertion	Fold, cut and sewing sequence
Fabric direction	MD/CD stretch and shrinkage are different	Roll direction on every test and production panel

Do not copy a universal cut-down percentage. Start with the frame supplier’s profile information, then validate it with the chosen fabric, heat process, keder and sewing method.

How Should Light Diffusion Be Tested?

For a backlit SEG project, approve the fabric inside the real LED box. A tabletop sample cannot show the effect of LED pitch, box depth, brightness and edge lighting.

Print white, 25% gray, solid colors, a gradient and a dense black area.
Install the fully sewn sample in the intended frame.
View it first with the LEDs off, then with the LEDs on.
Check the center, four corners and both side edges.
Look for hotspots, bands, dark zones, pinholes and color shifts.
Photograph each sample with the same camera settings for comparison.

What Sample Size Should Be Tested?

Sample	Useful For	Not Enough to Approve
A4 or A3 swatch	Surface, white point, hand feel and basic color	Stretch, corners and frame fit
0.5m × 0.5m printed sample	Ink, heat and basic shrinkage comparison	Large-panel cutting allowance
1m × 1m finished frame sample	General sewing, edge insertion, tension and corner fit	Long-wall accumulation without another test
1m wide × final-height strip	Tall-frame shrinkage and sag behavior	Full-width behavior
Full-size pilot panel	Large, repeated, tightly registered or high-risk jobs	Only variables outside the tested setup

UNISIGN SEG Fabric Starting Points

These four unprinted polyester fabric rolls are practical starting points. They are not universal approvals. Review the current TDS and test the finished panel in the actual frame.

Backlit woven

SDB190

190gsm
Direct / transfer sublimation
Up to 3.2m / 126 in
100m / 110 yd roll

View SDB190

Backlit knitted

SDB270

270gsm
Direct / transfer / latex listed
Up to 3.2m / 126 in
100m / 110 yd roll

View SDB270

Non-lit display

DSP09

230gsm
Warp knitted, slight stretch
Up to 3.2m / 126 in
100m / 110 yd roll

View DSP09

Blockout

DSP-BLK-01

260gsm
Black back, slight stretch
Up to 5.0m / 197 in
100m / 110 yd roll

View DSP-BLK-01

For more backlit, non-lit, blockout, woven and knitted options, compare the complete UNISIGN SEG fabric roll range.

SEG Fabric Print and Frame Test: 8 Steps

1Record the frame
Measure the opening, diagonals and extrusion groove.

2Select the fabric
Choose backlit, non-lit or blockout and confirm printing compatibility.

3Mark the sample
Record MD/CD, dimensions and batch before printing.

4Print and heat
Use the intended printer, ink, paper and heat recipe.

5Measure change
Record shrinkage and image distortion after cooling.

6Cut and sew
Use the real keder, stitch line and corner method.

7Install
Check insertion force, corners, tension, wrinkles and sag.

8Approve and record
Save the fabric, batch, process and size correction for repeat orders.

Common SEG Problems and What to Check

Problem	Check First	Possible Next Test
Panel is too loose	Cut size, CD stretch, stitch line and keder movement	Repeat with measured size correction
Corners are too tight	Diagonal frame size, corner folds and uneven stretch	Test one finished corner in the real extrusion
Backlit hotspots	Fabric diffusion, over-stretch, LED pitch and box depth	Compare the same image under fixed LED settings
Graphic changes size after heat	MD/CD shrinkage, web tension, time and temperature	Repeat a marked heat test
Replacement graphic does not fit	Fabric batch, keder, stitch line and saved correction	Compare against the approved production record
Image looks distorted	Uneven horizontal/vertical stretch and artwork position	Use a printed measurement grid

What Should You Send for a Fabric Recommendation?

Backlit, non-lit or blockout application
Visible frame opening and extrusion drawing
Direct or transfer sublimation, UV or latex process
Required roll width and finished graphic size
Silicone or TPE edge specification
Target GSM and stretch behavior
Required FR standard and destination market
Order quantity and sample plan

Frequently Asked Questions

What is the best fabric for a backlit SEG frame?

Start with a fabric made for backlighting. Test light diffusion, black density, white point, shrinkage and finished fit inside the actual LED box.

Can the same SEG fabric be used for backlit and non-lit frames?

Sometimes, but it is not automatically the best choice. Backlit fabric must transmit and spread light. Non-lit fabric normally needs stronger opacity and a smooth matte face.

Is woven or knitted fabric better for SEG?

Neither is always better. Woven fabric often gives more dimensional control. Knitted fabric often gives more stretch and fold recovery. Test the behavior required by the frame.

How much smaller should an SEG graphic be cut?

There is no safe universal percentage. Measure heat shrinkage, installed stretch, keder size, stitch line and the exact extrusion, then approve a finished sample.

What silicone keder size should be used?

Use the size specified for the aluminum profile, then test insertion and holding force with the selected fabric. Record width, thickness, hardness and supplier.

How large should the first SEG test be?

A finished 1m × 1m panel is a useful general starting point. Use a full-height strip or a full-size pilot panel for large, tall, tightly registered or high-risk jobs.

Should shrinkage be measured before or after sewing?

Measure before heat, after heat, after sewing and after installation. These stages answer different questions and should not be combined into one guessed number.

Does a backlit SEG sample need to be tested with LEDs on?

Yes. Test it in the intended lightbox with LEDs both off and on. This is the only reliable way to see hotspots, bands, color loss and edge effects.

Compare SEG Fabric Rolls and Request Samples

Send the frame type, extrusion, print process, finished size and application. UNISIGN will help you build a shorter list of unprinted polyester SEG fabric rolls for testing.

View SEG Fabric Rolls Request Samples and Technical Data