Why Handmade Paper Curls and How to Flatten It
A softly deckled sheet that lifts at the corners can be frustrating when you are preparing a watercolour, addressing wedding invitations or photographing a finished piece. Yet why handmade paper curls is also closely tied to what makes it so appealing: long natural fibres, gentle processing and a beautifully responsive surface. Unlike heavily pressed, machine-made paper, handmade paper has a little more life in it.
Curling is rarely a sign that a sheet is poor quality. More often, it is paper reacting to moisture, temperature or an uneven drying process. Once you understand that response, you can store, prepare and flatten your paper with confidence, while preserving the tactile character that makes cotton rag, khadi and recycled papers so special.
Why handmade paper curls in the first place
Paper is made from fibres, and fibres respond to moisture. Cotton rag paper, for example, is formed from cotton linters or recycled textile fibres which absorb and release water from the surrounding air. When one side of a sheet takes on more moisture than the other, it expands slightly. The drier side stays more stable, so the paper bends towards it.
This can happen after a sheet has travelled through changing climates, been stored close to a radiator, or moved from a dry studio into a humid room. A parcel that arrives beautifully flat may develop a gentle curl after a few days on an open desk. That does not mean anything has gone wrong. It means the sheet is finding its balance in a new environment.
The handmade process adds its own subtle variation. Fibres are dispersed in water, lifted in a mould, pressed and dried in small batches. The resulting sheet is wonderfully individual, but its thickness, texture and fibre direction are not always as uniform as mass-produced paper. A pronounced deckle edge may also look as though it is curling when it is simply retaining its naturally undulating handmade finish.
Moisture is the usual culprit
A damp brush, watery ink wash, envelope glue or even a cool drink placed nearby can introduce moisture to one face of the sheet. Watercolourists see this most clearly: as a wash dries, the wetted side contracts and the paper can buckle or curl. Lighter-weight sheets are naturally more susceptible, while a heavier cotton rag paper has more structure and will usually settle more readily once dry.
Humidity works more slowly but can be just as influential. Paper kept in a steamy kitchen, conservatory or bathroom-adjacent workspace may soften and wave. Conversely, central heating can dry it out quickly and pull the edges upwards. This is especially noticeable with uncoated, absorbent papers, which are prized for their natural feel and graceful way with ink, paint and letterpress.
There is a trade-off here. A highly absorbent sheet welcomes pigment and ink with an organic softness, but it will be more responsive to water than a heavily sized, tightly compressed card. For calligraphy, invitations and gift presentation, that responsiveness is part of the material’s charm. It simply asks for thoughtful handling.
Drying unevenly creates tension
Paper often curls after a creative process because it has dried too quickly or unevenly. A painted sheet left on a warm windowsill, for instance, may dry at the edges before the centre. A glued envelope liner can draw one corner out of shape as the adhesive cures. Digital printing may add a little heat and moisture, while hand-applied paint, paste or wax can affect one surface more than the other.
The aim is not to make handmade paper behave like office copier paper. Instead, give it time to dry gradually and evenly. A sheet that feels faintly cool to the touch may still contain moisture, so resist flattening it immediately after painting or printing. Let it dry fully before deciding whether it needs any intervention.
How to flatten handmade paper gently
For a mild curl, the simplest approach is often the best. Place the sheet between two clean, smooth pieces of unprinted paper or acid-free tissue, then lay it beneath a large, flat weight. A portfolio, clean board or a few substantial art books will do the job nicely. Leave it for 24 to 48 hours in a dry room away from direct heat.
The protective layers matter. They prevent texture, pigment or small surface imperfections from transferring to the weight above. For a precious painted piece or wedding stationery, use clean blotting paper if you have it, replacing it if it becomes damp.
If the curl is more determined, lightly humidifying the paper can help it relax before pressing. This should be done with restraint. Place the sheet in a clean, enclosed container alongside, not touching, a barely damp sponge or cloth for a short period. The goal is to introduce gentle ambient moisture, never to wet the paper. Check it regularly, then sandwich and press it once it has softened slightly.
Avoid spraying handmade paper directly unless you are experienced with the particular stock and have tested an offcut first. A fine mist can leave marks, disturb water-soluble media or create new ripples. Equally, an iron is rarely the first choice. Direct heat can flatten texture, alter sizing, scorch delicate fibres or leave an unwanted sheen, particularly on natural and deeply textured sheets.
For watercolour and ink work
When you know a piece will receive generous washes, preparing it beforehand is more effective than correcting it afterwards. Artists often stretch paper by dampening it evenly, securing it to a board and allowing it to dry under tension before painting. This is most useful for lighter watercolour sheets and broad, wet applications.
For smaller studies, a simple alternative is to tape the edges of dry paper to a rigid board before you begin, using a low-tack artist’s tape suited to delicate surfaces. Work with considered amounts of water and allow the painting to dry flat. The right method depends on the paper weight, the amount of water in your technique and whether the deckle edge needs to remain visible.
Do test first. Handmade paper varies beautifully from batch to batch, and a process that suits a smooth cotton rag sheet may not be ideal for a softly textured recycled paper.
Storing paper so it stays beautifully flat
Good storage prevents many curling issues before they begin. Keep unused sheets flat rather than rolled, ideally in a portfolio, archival box or sturdy drawer. Support them with a clean board above and below, especially if you have a collection of several sizes.
Try to keep paper away from direct sunlight, radiators, open windows and areas with rapid shifts in humidity. It does not need laboratory conditions, but consistency helps. If your studio tends to be damp, a closed storage box offers more protection than an open shelf. If the air is very dry, avoid storing sheets directly beside a heat source.
Before starting a special project, let the paper rest in your workspace for a day or two. This allows it to acclimatise to the room before you paint, write or print on it. It is a small ritual, but a valuable one for event stationery where every sheet needs to look considered and composed.
When curling is a feature, not a fault
Not every lift at an edge needs to be pressed away. Handmade paper is allowed to show its origins. A gently waving deckle, a lightly cockled painted surface or a tactile folded card can bring warmth and authenticity to a finished piece. In an age of perfectly uniform surfaces, those details quietly signal that something has been made with care.
For framing, a professional framer can advise on mounting methods that support the sheet without forcing it unnaturally flat. For invitations and correspondence, press the finished work only if the curl interferes with presentation, posting or folding. A little movement can be part of the story, particularly when the paper is paired with silk ribbon, wax seals or hand-lettered details.
The Natural Paper Company’s handmade papers are created to be used, enjoyed and admired, not treated as fragile museum objects. Handle them with clean hands, give them an even environment and be patient when moisture enters the process. The slight curl that first catches your eye is often simply the paper reminding you that it was made from honest fibres, one beautiful sheet at a time.