Curtain Fabric Specification Guide: A Quality Inspector’s Checklist for Velvet, Upholstery, Outdoor Fabrics & Rugs

If you're specifying fabrics for a new contract project, this checklist is for you. I'm a quality/compliance manager at a textile company. I review every fabric collection before it reaches our sample library—roughly 200 pieces a year. I rejected close to 7% of first deliveries last year, mostly because of color mismatches and missing batch documents. This is the process I actually use when I evaluate a curtain fabric, a velvet upholstery range, or an outdoor fabric collection.

It's not a design guide. It's a checklist for the ten minutes after the design meeting, before you commit to a production order.

I'd rather spend 10 minutes explaining what to check than deal with a mismatched fabric delivery later.

Who This Checklist Is For

Use this if you are a B2B buyer, distributor, manufacturer, or specifier choosing between fabric sources. You might be looking at a new sofa fabric distributor, checking whether a velvet fabric supplier can deliver, or comparing romo outdoor fabrics against another contract range. The names change; the checks stay the same.

Before you start, gather three things: a physical sample of the fabric, the supplier's specification sheet, and the product's end-use details. This checklist works best when you can put the fabric in your hands.

The Six Steps in My Fabric Approval Checklist

1. Start with the end use, not the pattern

Before you fall in love with a colorway, write down what the fabric has to survive. Curtains in a south-facing room need lightfastness. Sofa upholstery needs abrasion resistance. Outdoor fabric needs UV and water resistance. A fabric that is beautiful in the hand can fail in the room. People assume expensive fabric is automatically better. Actually, fabric that solves the performance problem can command a higher price—the causation runs the other way.

For curtains, don't stop at the color. Ask about width, vertical pattern repeat, and drape. If you're specifying a striped or patterned fabric, the repeat affects how much material you need. A "perfect" fabric with a 68 cm repeat can be the wrong choice for a room with many windows and limited widths. (Not that I've made that mistake—at least not twice.)

2. Check the construction and finish on a physical sample

Digital photographs don't show weight, hand feel, or finish. For velvet, ask for pile density and pile height. For linen, ask for thread count and weight per square meter. For rugs, including romo rugs if you're specifying them, inspect the backing and pile height in person. (The top-down photo rarely shows either.)

When I compared two velvet options side by side—same color name, same fiber blend, one from a local agent and one directly from the mill—I finally understood why the finish matters. The agent's sample looked fine in the photo, but the actual pile height was noticeably shorter. The "premium" velvet felt thinner than the standard one (which, honestly, made me question the sampling process).

Don't hold me to this, but many velvet mills list pile height in millimeters. Make them write it down. If they won't, that's useful information too.

3. Put a number on color expectations

Color approval by eye is fine for a single roll. For a production order, specify a tolerance. We use a Delta E of less than 2 for brand-critical colors, following Pantone Color Matching System guidelines. Delta E between 2 and 4 is noticeable to trained observers; above 4 is visible to most people.

Ask your dye house or fabric supplier to send a color report with the batch. If they say "we'll match the sample," ask which sample and under what light. We reject more first deliveries for color inconsistency than for any other issue. A digital color scan is helpful, but it only tells you the color of one small area on one roll.

4. Demand batch-specific documentation, not brochure claims

This is the step most people skip. I only believed in batch numbers after we skipped them once and accepted 800 meters of curtain fabric that didn't match the approved sample. The supplier said it was "within industry standard." It wasn't within our standard. We rejected the batch, they redid it at their cost, and we lost about three weeks. Now every contract we send out includes batch number, roll number, width, weight, finish, and color target.

If a velvet fabric supplier can't provide a batch report before the order, treat it as a warning sign. A generic marketing sheet is not a specification. For a curtain fabric specification guide, the batch report should also include the vertical repeat measured from the actual production run, not the design file.

5. Ask for test data that matches the actual use case

For upholstery, ask for a Martindale abrasion report (ISO 12947). For outdoor fabrics, ask for lightfastness (ISO 105-B02) and water repellency results. For curtains, check draping and lightfastness. But don't just ask for a certificate—ask whether the test was run on the same construction, finish, and colorway you intend to order.

When someone asks me whether romo outdoor fabrics are suitable for coastal sun, I don't answer with the brand range. I ask to see the lightfastness rating for the specific colorway. Dark colors and bright colors can behave differently on the same base cloth. The same applies to any outdoor fabric range you're considering—not just romo.

6. Read the compliance and care label before you commit

Flame retardancy is not a universal fabric property. If you need FR compliance, ask for the report for the exact product and treatment. A fabric can be FR in one colorway or finish and not in another. Outdoor fabrics sometimes require a chemical finish that changes the hand feel. We learned this the hard way when a "dry-clean only" finish failed a standard laundry test (unfortunately, after the first production batch). If you are a sofa fabric distributor, your customer may never ask about care instructions until after a spill. Be ready to answer with the label in front of you.

For rugs—including romo rugs if you specify them—ask about back-coating and shedding. We've seen beautiful wool rugs rejected because the backing didn't lie flat after installation. (Mental note: always check a corner, not just the center.)

Common Mistakes I See in Fabric Specifications

After a few years of reviewing deliveries, the same issues come up again:

• Specifying by collection name instead of construction details.
• Approving color from a monitor without a physical sample.
• Assuming the first sample represents the whole production lot.
• Ignoring batch numbers until a mismatch happens.
• Not keeping a retained sample from the approved batch.

Keep a sealed cutting from every approved batch. If a dispute happens later, you'll need something both sides can agree on. We scan our retained swatches before filing them (I really should have done that sooner).

What to Do Next

If you only change one thing, make it step four: ask for batch-specific documentation before you order. The rest of the checklist is easier once you know what you're approving. An informed customer asks better questions and gets better deliveries. And when the supplier knows you'll check, the samples tend to improve too.