Fabric, linings and fading: what a curtain is made of and how it lasts

Sun and damp decide how long a curtain lasts, and the lining decides most of what it does. This chapter chooses a fiber and weave for the window, a lining for the need, and a care plan, and says plainly what UV film can and cannot do about fading.

1. Fibers in sun and damp Understand

A curtain hangs in the hardest place in a house for fabric: in front of glass, in sun, beside a cold surface where damp collects. What it is made of decides how long it keeps its strength and color there. The face fabric is the part you see; the lining, covered in Linings: what each layer does, decides most of what the curtain does.

What sun does to fabric

Michigan State University's extension bulletin Fabrics for the Energy-Conscious Home (1984) says that sunlight deteriorates almost any fabric, and that grime, fumes, heat and humidity speed the damage. Physical principle It also notes that the dye chemistry that gives a fabric its color can start sun damage, and suggests asking for dyes treated for lightfastness, which is a dye's resistance to fading in light. Sun does two separate things: it fades color, and it weakens fiber until a curtain splits along a fold. A curtain can lose strength before it visibly fades, so a split at the leading edge after a few summers is the same process as fading, not a different fault.

Fibers compared

The most complete published comparison of fibers at windows is in extension bulletins from 1971 to 2008. They name fibers, not today's blends and finishes, but the behavior of a fiber in sun has not changed. The table combines Michigan State's sunlight column (1984) with New Mexico State University's guide Selecting Fabrics for Home Furnishings (marked for revision in 2008 and still hosted unrevised).

Sources: Michigan State University Extension Bulletin E-1772 (1984); New Mexico State University Guide G-401. Both are dated; they describe fibers, not branded fabrics or finishes.

Read the table as three groups. Acrylic, polyester and glass fiber hold up best in sun. Cotton, linen, nylon and wool lose strength gradually, so they last longer lined or in a window with less direct sun. Silk, rayon and acetate do worst at a sunny window and are the ones the bulletins steer away from there. A blend sits between its fibers; how far depends on the proportions, which the fiber label gives.

Weave and color

A firm, closely woven fabric lasts longer at a window than a loose one. The University of Idaho's 1971 extension leaflet Be an "Aware" Shopper says firm, closely woven fabrics are more durable and more sun resistant than loose weaves, and New Mexico State's guide says loose weaves and satin weaves wear quickly. Physical principle A satin's long floating yarns catch and wear; a loose weave lets each yarn take more of the sun.

Color matters too. Michigan State's bulletin notes that lighter colors reflect more light. A pale curtain at a sunny window stays cooler, and its fading shows less than on a dark, saturated color. That is a tendency, not a rule: dye chemistry decides how fast a given color fades.

Damp rooms

Bathrooms, kitchens and windows that run with condensation add moisture to the list. Cotton is subject to mildew in New Mexico State's table, and Michigan State notes that too much moisture absorption makes drapery stretch or shrink. Physical principle In a damp room the default is a synthetic that absorbs little water, such as polyester, or a covering that is not fabric; Curtains, shades, blinds and shutters compares the kinds. Condensation itself, and what to do about it, is in Heat, cold and condensation.

2. Why natural fibers move

Natural fibers take up water from the air and give it back, and a curtain made of them changes length with the weather. It is most noticeable in linen.

The Canadian Conservation Institute explains the mechanism in Textiles and the Environment (CCI Notes 13/1): at high relative humidity, fibers swell, and in most woven textiles that swelling makes the fabric shrink, especially along the warp, the lengthwise yarns. Physical principle A curtain's length usually runs along the warp, so the effect shows as a change in where the hem sits.

A custom drapery workroom describes what that looks like in a home. Field Work Design Craft, writing about custom linen drapery, says linen relaxes rather than stretches like cotton, that temperature and humidity make linen drapery lengthen and shorten, and that linen blends are less affected. In a second post on natural fabrics for draperies, the same workroom says lengths can differ considerably some time after installation, and that the fix is to re-hem. Preference Neither post gives a measurement, and we found no source that does.

What this means when choosing:

• A pure linen curtain whose hem is meant to just touch the floor, or to sit a fixed distance above it, will move. A blend moves less, by the workroom's account. A polyester moves least.
• A curtain meant to puddle on the floor hides the movement. One that clears the floor by a small amount shows it.
• If you make your own linen curtains, leave a deep hem so there is fabric to let down, and plan to check the length after a season. Buying, ordering or making covers hems and allowances, and Measuring for curtains covers lengths and the allowance some makers ask for in linen.

Wool and cotton take up moisture too, and New Mexico State's table notes that rayon may shrink or stretch. Synthetics such as polyester and acrylic take up little and are steadier. Physical principle

3. Linings: what each layer does

A lining is a second fabric sewn or clipped behind the face fabric, facing the window. It is the cheapest way to change what a curtain does, and it protects the face fabric from the sun. An interlining is a soft layer between the face and the lining, hidden on both sides.

Eastern Accents, a custom drapery maker, sets out the kinds in its Drapery Lining FAQs, and the University of Idaho's 1971 leaflet names the same purposes for standard lining: it improves the drape, looks finished from outside, and protects the drapery fabric from sun and soil.

Sources: Eastern Accents, Drapery Lining FAQs; Michigan State University E-1772 (1984); weights from the Kirsch Wrought Iron 2024 Price Guide's fabric weight table. Product-specific Other makers' linings differ.

The weights matter for hanging. Every layer adds to what the rod and brackets carry, and an interlined, blackout-lined curtain can weigh several times what the face fabric alone does. Curtain weight and hardware adds the layers up.

A lining can matter more than the fiber

Michigan State's 1984 bulletin makes a point worth keeping: for a sunny room, a sun-sensitive fabric with a highly reflective lining can outperform a sun-resistant fabric hung unlined. Physical principle The lining takes the sun, and the face fabric sits in its shade. If you love a cotton or linen that the fiber table leans against, a good lining is often the answer.

Choosing by the first need

• Privacy at night: standard lining at least; blackout if the face fabric is light or thin. A lined curtain also shows the street a uniform face, which matters where a lease or an association rule asks for a particular color from outside (Privacy by day and by night).
• Darkness for sleep: blackout lining, with the edges planned, as Darkness for sleep, and the edges explains.
• Heat or cold at the window: interlining, or a reflective lining at a sunny window; how much a curtain can do, and only when it is closed at the right times, is in Heat, cold and condensation.
• Protecting a fabric you care about: any lining; reflective or bump for a sun-sensitive face in strong sun.
• Daylight: no lining, or a sheer layer that is meant to let light through and is replaced when it wears.

4. Fading, and what UV film can do

Fading is the part of this subject most often oversold. The conservation sources are clear about what causes it, and the window film industry's own association is clear about what film can and cannot do.

Fading adds up

The Canadian Conservation Institute's note on textiles says light damage is cumulative and irreversible, and that exposure is light level times hours: 100 lux for 400 hours does the same as 50 lux for 800 hours. Physical principle Lux is a measure of how much light falls on a surface. So a curtain does not fade in a bad week; it fades a little every sunny hour, and the fading does not come back. What you control is how bright the light is and how many hours it falls on the fabric.

UV is not the whole cause

Ultraviolet light is the harshest part of sunlight for fabric, and it is the part most products address. It is not the whole story. The Canadian Conservation Institute's guide to light as an agent of deterioration says that for light-sensitive colors, UV usually contributes less than half of fading and often only a tenth, and that the only way to reduce fading is to reduce light exposure. Physical principle The International Window Film Association's Advanced Solar Control Education Guide 2026 lists at least five causes: UV, visible light from sun and lamps, humidity and heat, the dye's own fastness, and chemical vapors, and says natural dyes and natural fibers fade faster than synthetics.

What window film does

Clear UV-filtering film on the glass cuts UV without cutting much visible light. The film association's FAQ says film can reduce the sun's UV by up to 99 percent, and the Skin Cancer Foundation's page on UV window film (updated December 2024) says film can block more than 99 percent of UVA and UVB, and that ordinary window glass filters most UVB but lets UVA through. Product-specific

The same FAQ says no window film can eliminate fading, and the association's education guide says no film or glazing product will totally prevent or stop fading. Physical principle Two statements from the industry's own association, and the conservation institute's point about visible light, agree: film slows fading by removing most UV, and visible light keeps fading colors behind it.

Read a UV percentage with care. The National Park Service's Conserve O Gram 3/10, Choosing UV-Filtering Window Films (August 2004) explains that "98 percent of UV filtered" claims usually cover only the range from 325 to 380 nanometers, while UV that passes glass runs up to 400. Product-specific A high percentage over a narrow range can leave some UV through. Ask what range the figure covers; Labels and spec sheets sets this out.

Two cautions before film goes on. The Canadian Conservation Institute notes that films may void the warranty on sealed insulating glass windows, so ask the window maker first. Ask the authority And in a rental or under an association's rules, film can count as a change to the window; ask in writing before applying it.

What a household can do

• Cut the hours. Close a shade or curtain in the hours of direct sun, when the room is empty. This is the one remedy the conservation sources say works on all light, not just UV.
• Line the curtain. The lining takes the sun and the face fabric is shaded.
• Choose fibers and colors that hold up. Acrylic and polyester, firm weaves, and a maker's lightfastness claim where there is one.
• Add UV film where the window maker and the lease or association allow it, as one layer of the plan rather than all of it.
• Move what you care about out of the patch of direct sun. The fading of a rug or sofa is the same process as the curtain's.

5. Labels and care

The fiber label

Fiber content is the label you can count on. The Federal Trade Commission's rules under the Textile Fiber Products Identification Act, 16 CFR Part 303, cover curtains, casements and draperies, so they carry fiber content. The same rules exclude curtains and draperies made principally of slats, rods or strips of wood, metal, plastic or leather, which is to say blinds and some shades. Read the percentages: "linen blend" can mean a little linen or a lot.

The care label

A care label is a different matter. The FTC's care labeling rule, 16 CFR Part 423, covers clothing and fabric sold by the piece for making clothing. Curtains and draperies are not in its definitions, so by our reading the rule does not require a care label on them. Ask the authority Many makers add one anyway. Where there is none, ask the seller how the curtain is cleaned before you buy, and write the answer down.

Cleaning lined curtains

The University of Idaho's 1971 leaflet says lined draperies are usually dry-cleaned, because washing can shrink the layers unevenly and pucker the curtain. Convention The face fabric, lining and interlining are different fibers and shrink by different amounts. A curtain with a lining on its own rod, or clipped on, avoids the problem: each layer is cleaned by its own method. Between cleanings, we take dust off with a vacuum's brush attachment on low suction. Preference

Before cleaning any fabric by a new method, try it on a hidden corner or a spare piece first. Test it Cleaning by surface in Learn Home Finishes covers testing a cleaning method on fabric and other finishes.

The care plan

A care plan is one line per curtain: what the face, lining and interlining are, how each is cleaned, how often, and what to check each season (the leading edge for splits, the hem for length, the side toward the window for fading and mildew). Write it in the fabric and lining column of the Options for each window sheet, next to the choice.

7. See it See it

• Drapery Lining FAQs, Eastern Accents: two pages that tell the linings apart in a maker's words.
• Fabrics for the Energy-Conscious Home, Michigan State University (1984): the fiber-in-sunlight table and the reflective lining finding, in a scanned extension bulletin.
• FAQ, International Window Film Association: what film does for UV and fading, from the industry's own association.
• Natural fabrics for draperies, Field Work Design Craft: a workroom's account of linen moving with the weather.

8. Practice Practice

Minimum: one window: its hours of direct sun noted, a fiber and weave chosen, a lining chosen for its first need, and the care method written down. Time: about 30 minutes, plus waiting for the seller's answer on care. Materials: the Window survey or a note of the window's sun, the fabric's label or listing, a sample of the fabric and of a lining if you can get them, and a pencil.

1. Note the sun and damp. From the survey, or by looking, write how many hours of direct sun reach the glass on a clear day, and whether the room is damp or the glass runs wet.
2. Choose the fiber and weave. Find the fiber, or the blend's main fibers, in the table or on Fabrics and linings. Hold the fabric up to a lamp: a firm, close weave shows little light between the yarns.
3. Choose the lining. From the window's first-ranked need, pick standard, blackout, reflective or interlined. Hold the lining sample behind the fabric at the window, by day and with a lamp at night, and look from both sides.
4. Read the label and ask about care. Write down the fiber percentages. If there is no care label, ask the seller how it is cleaned, and whether the lining is sewn in or separate.
5. Write the choice. In the Options for each window sheet, put the fabric and lining with the care method in the fabric and lining column, and the reason in the why column.

9. Your windows Your windows

10. Check your work Check your work

Criteria

• Do you know roughly how many hours of direct sun the window gets, and whether the room is damp?
• Does the fiber suit that sun and damp, or is it protected by a lining if it does not?
• Is the weave firm and close, especially at a sunny window?
• Does the lining serve the need the window ranked first?
• Have you read the fiber percentages, and do you know how the curtain will be cleaned?
• Is the choice, with the care method, on the choices sheet?

Worked example

Walt's choice, checked (fictional). Sun and damp: south, strong winter sun, wet glass on cold mornings; noted. Fiber: a linen and cotton blend, which the table leans against in strong sun, protected by a lining and an interlining. Weave: he holds it to a lamp and it is close. Lining: chosen for the cold, his first need. Label: not yet read, so the percentages are an assumption; that is open. Care: open until the seller answers and a spare piece is washed. Two criteria are unmet until the label and the seller answer, and the choice is written on the sheet with both marked open.

Common mistakes

• Treating UV film as the answer to fading. It removes most UV; visible light still fades color, and the industry's own association says film does not stop fading. Cut the hours as well.
• Choosing silk or a loose weave for a sunny window unlined. The bulletins rank silk worse than cotton in sun, and loose weaves wear quickly. Line it, or choose another fabric for that window.
• Washing a sewn-in lined curtain. The layers shrink by different amounts. Ask first, or make the lining separate.
• Reading "linen look" or "linen blend" as linen. The fiber label gives the percentages; read them.
• Setting a linen hem to the floor with no spare. It will move with the weather. Leave fabric to let down, or let it puddle.

What is still unresolved

This chapter settles the fabric, lining and care, not the size or the hardware. How much fabric to buy and how to sew linings in is in Buying, ordering or making; how much the lined curtain weighs and what will hold it in Hardware and installing and Curtain weight and hardware; what a lining does for heat and condensation in Heat, cold and condensation. How fast a particular fabric fades is the maker's to say, and whether film may go on the glass is the window maker's and, in a rental or association, the landlord's or the association's.

11. Knowledge check and scenario

Checklist

• The window's hours of direct sun and any damp noted.
• A fiber and weave chosen for that sun and damp.
• A lining chosen for the window's first-ranked need.
• The choices sheet names a fabric and lining for the window, with the care method.
• A spare piece sun-tested against one kept in a drawer. (Go deeper; optional)
• The conservation fading table read, and the curtain's sun hours compared with it. (Go deeper; optional)