Has the tape stretched

A tape that has stretched still looks fine and still has its printed numbers exactly where they always were. The check for stretch is not visual - it is laying the tape against something you already trust and reading off any disagreement.

The check

Lay the tape flat, unrolled, next to a rigid ruler you have reason to trust, with both zeros aligned. Read where the tape's 10 cm mark and 20 cm mark fall against the ruler's scale. If the tape's marks land past where the ruler says they should, by a millimetre or more, the tape has stretched under whatever tension it was under during printing versus now, and every reading you have taken with it read a little long.

A bank card is a shorter, faster version of the same check if a longer known-accurate ruler is not to hand, since a standard card is 85.60 by 53.98 mm and gives you a second fixed reference over a shorter span.

Why this happens and how often to do it

Tapes stretch with age and with use - the fibres or backing loosen slightly each time real tension is applied, and the effect compounds slowly over months rather than showing up after one use. This is worse for cloth tapes and least for fibreglass-reinforced ones, which is the material comparison worth reading if you are choosing a tape rather than checking one you already own. Because the drift is gradual, a tape that passed this check six months ago is not guaranteed to pass it today, and repeating the check every few months, or whenever a reading looks unexpectedly different from the last one, is the practical schedule.

What a failed check means

A stretched tape does not need to be thrown away necessarily - if you know it reads long by a known amount, you can subtract that amount - but a fresh, unstretched tape is the simpler fix and removes the need to remember a correction. A tape that fails this check by more than a millimetre or two across a 20 cm span is worth replacing outright, since the correction itself becomes a new source of error if you get it slightly wrong.

This has no bearing on a rating from a photograph. Rate Cock does not use a tape at all, and neither does a human judge, a photo-based score, or an AI model reading an image - stretch is a property of physical tape, not of a judgement about a picture.