Reading a towel spec sheet — what each line is actually promising

A towel specification sheet looks precise: a column of numbers and standard names, each with a unit beside it. Most of the lines promise less than they appear to, and the gaps are where a first order and a reorder start to differ. Reading a sheet well mostly means asking of each line one question — measured how, and when?

Weight: GSM is a nominal figure, piece weight is a different one

GSM is the fabric's weight per square metre, and our guide to hotel towel GSM covers what it does and does not tell you. On a spec sheet there are two further things to check. First, whether the figure is a target or a minimum, and what tolerance applies — a towel quoted at 500 GSM that lands a little either side is normal, but "a little" should be a stated number, not an assumption.

Second, whether the sheet quotes GSM or weight per piece, because they are easy to mix up. Piece weight is GSM multiplied by the towel's area: a 70 × 140 cm bath towel has an area of 0.98 square metres, so at 500 GSM it weighs about 490 g. Two suppliers quoting "500" and "490" may be describing the same towel.

Size: finished, and measured when

Towels shrink the first time they are washed, so the size on the sheet needs a qualifier. Ask whether it is the size as woven, as finished, or after a stated number of washes — and whether it is length and width of the towel body or includes the border and fringe. A bath towel specified at 70 × 140 cm that arrives at that size, then comes out of the first wash smaller, has met the sheet and still disappointed the buyer.

Construction: the line that names the product

"Terry", "waffle", "dobby border" and "zero twist" each name a different product, so this line should be specific. Check that the sheet says how the pile is built — double-sided or one-sided, ringspun or zero twist — and that the border is woven rather than printed or sewn on, since that decides whether the border survives commercial washing in step with the rest of the towel. Our guides on towel constructions and on terry versus woven towels cover what each choice changes.

Colour: the dyeing method, not just the shade name

A shade reference — a Pantone number or a swatch — says what colour is wanted but not how it is achieved. The sheet should also say how the towel is dyed, since that decides how the colour behaves in a pool, in sunlight and through years of washing. The reference that bulk dyeing is checked against should be a physical approved lab dip, as our guide on lab dips explains, not a number on a screen.

Colourfastness: a grade only means something with its test

Colourfastness lines usually show a grade with no context. The grades come from standard tests in the ISO 105 series: colour fastness to washing (ISO 105-C06), to rubbing (ISO 105-X12) and to light (ISO 105-B02) are the ones most relevant to towels. Washing and rubbing results are graded on a scale of 1 to 5, and light fastness on a scale of 1 to 8; higher is better on both.

A grade is only meaningful alongside the test it came from, so look for the standard named, the grade for each condition — colour change and staining on other fabrics are graded separately — and a test report you can request, not only a figure typed onto the sheet. A sheet that says "good colourfastness" has not told you anything.

Shrinkage: how much, after how many washes

Dimensional stability is the figure that tells you how far the towel will change in use. It should be stated as a percentage change in length and width, after a defined washing and drying procedure and a stated number of cycles. As with weight, the useful part is that the sheet commits to a limit; what limit is acceptable depends on your product and your customers, so it is worth deciding before you see the quotation.

What a blank or "on request" line means

Some lines on a sheet are left blank or read "confirmed on quotation", and that is not automatically a bad sign. Weight, size and finish depend on the application, and a supplier who fills in a number before knowing the application has guessed. What matters is that every line has a number before you approve the specification, and that the approved physical sample is the reference the numbers are checked against.

What to ask for

• GSM or piece weight, which one it is, and the tolerance
• Finished size, and whether it is measured before or after washing
• The construction in full: pile, yarn and border
• The dyeing method, and the physical lab dip as the colour reference
• Colourfastness grades with the test standard named, and the test report
• Shrinkage limits, and the washing procedure they are measured under
• The tolerance on every line, so "approximately" becomes a number

Send us the towel you are specifying and where it will be used, and our export team will return a sheet with every line filled in, and a physical sample made to it, before you commit to an order.