How Jigsaw Puzzles Are Made

A cardboard jigsaw is a printed sheet of paper glued to about two millimetres of recycled board and cut, in a single stroke, by a tool that somebody bent into shape by hand. Almost everything that makes one puzzle better than another is decided inside that sentence, and none of it is visible once the box is sealed.

It starts with a picture that can survive being cut up

Long before anything is printed, somebody has to licence an image. Puzzle publishers rarely own the artwork. They licence it from illustrators, photographers, photo libraries, museums and galleries, or from the rights holder of a film or a brand, usually for a fixed term, a fixed territory and a fixed print run. That contract is why a title disappears and never returns, and why the same painting can appear from two different publishers in two different countries.

The choice is not made on beauty alone. An image has to work as a puzzle, and three things decide whether it does.

Resolution. A 1000 piece puzzle finishes at roughly 70 by 50 cm. Printed at a normal commercial 300 dots per inch, that needs a file of about 8,200 by 5,800 pixels. A gorgeous photograph that only exists at web size is not a candidate.

Shape. The picture has to crop to the aspect ratio of the format without losing its subject. A tall painting and a panoramic photograph are not going into the same box.

Buildability. This is the one people underestimate. A picture needs distinct regions a puzzler can anchor to, and enough local texture that two pieces from the same area do not look identical. Enormous flat sky is not automatically wrong, but it changes the puzzle from a pleasant evening into an endurance event, and the publisher has to decide on purpose whether that is what it is selling.

Prepress, where the picture becomes printable

The approved image is separated into the four process inks: cyan, magenta, yellow and black. Each becomes its own printing plate. The file is scaled to the exact finished size, an allowance is added around the edge for trimming, and the whole thing is compensated for the way ink spreads slightly into paper on press, so the printed sheet matches the proof rather than the screen.

A proof is produced and signed off. Then the box artwork goes through the same process separately, because the lid is printed on different stock, and the lid image and the puzzle image are two different print jobs off one file. That is why a lid can be very slightly warmer or cooler in tone than the puzzle inside it. It is normal, and on a well run job it is invisible.

Printing the sheet

Almost every cardboard puzzle is printed by offset lithography, the same process used for magazines and packaging. Ink is transferred from plate to rubber blanket to paper, one colour per unit, at high speed. It is chosen for the same reason it is chosen everywhere else: at volume it produces consistent colour cheaply.

Two finishing decisions at this stage carry all the way through to how the puzzle feels on your table.

The first is texture. Better puzzles are printed on paper embossed with a fine linen pattern. Ravensburger says it prints its puzzles exclusively on linen embossed stock specifically to reduce reflections and flaring. If you have ever built a glossy puzzle under a ceiling light and found yourself tilting your head to see the pieces near the lamp, you already know what the linen finish is for.

The second is coating. A matt or satin varnish protects the ink from finger oils across the dozens of hours a puzzle spends being handled, and it controls glare. A high gloss puzzle photographs beautifully and builds badly.

The board, the part you never see

Under the picture is the material that actually decides whether the puzzle survives.

The industry standard is solid board made from recovered paper, sold to puzzle makers in grey and in blue. The blue is not decoration, it is just what a particular recycled furnish looks like, which is why the backs of puzzles from different factories are different colours. ESKA, one of the specialist mills supplying this trade, describes its puzzle board as three layers, 2 mm thick, made from 100% recovered fibre and certified to FSC and PEFC.

Three details on that board matter more than the number of millimetres.

Thickness ranges across the market. An older industry reference gives a common chipboard at 0.087 inches, which is about 2.2 mm. Premium European puzzles sit around the 2 mm mark. Cheap puzzles go thinner, and thinner board is the single easiest cost to remove from a puzzle without changing anything a customer can see in a photograph.

Laminating, and the days of waiting

The printed sheet is glued to the board under pressure, and this is the step where a puzzle is quietly made good or made disposable.

Adhesive is applied, the printed sheet is registered onto the board, and the sandwich is rolled or pressed flat so that no air is trapped. Many makers add a backing paper to the reverse at the same time. That backing is not there to look nice, it is there to balance the sandwich. Paper expands and contracts with moisture, so a board with paper on one face and nothing on the other will curl as it dries. Paper on both faces pulls evenly against itself and stays flat.

Then the sheets sit. The reference literature describes laminated sheets being left to dry for several days before they go anywhere near the press. Rushing that is exactly what produces the puzzle whose picture lifts at the cut edges, or whose pieces have started to smile upwards by the time they reach a table in a humid climate.

The die, the most expensive object in the building

Here is the part almost nobody knows about, and it explains most of what is odd about the puzzle industry.

Pieces are not cut individually. They are cut all at once, by a steel rule die: a slab of plywood, typically 15 to 18 mm thick, into which narrow slots have been cut along every single cut line. Into those slots go lengths of thin, razor sharp steel rule, standing about 23.8 to 25.4 mm proud of the board. Bent to the exact curve of every tab and blank. Tapped in by hand.

The modern workflow starts on a screen: the cut pattern is drawn in software, then the slots are cut by machine. The blades themselves still have to be formed and set, and at the premium end the design itself is still drawn by hand. Ravensburger states that its puzzle templates are hand drawn and its punching tools hand made, which is the mechanism behind its claim that no two pieces in one of its puzzles share a shape.

Around every blade, rubber is fitted. When the press lifts, the rubber compresses and then pushes the board back off the knives instead of letting it ride up and jam. Get the rubber grades or the placement wrong and you deform pieces on the way out.

The numbers are the interesting bit. An older industry account puts the making of a die for a 500 piece puzzle at around 400 hours of work, with the whole job from artwork to finished puzzle running to nearly 2,000 hours across about twelve months. Software and CNC have taken time out of that since. The shape of it has not changed: the tool is the long pole, and the tool is where the money is.

The cut pattern, and why 1000 pieces is not 1000

The pattern itself has to solve a geometry problem. The pieces need to be roughly square, roughly the same size as each other, and they need to tile the exact rectangle of the picture. So the cut sits on a grid, and the grid rarely multiplies to a round number.

A common 1000 piece layout is 38 columns by 27 rows, which is 1026 pieces. The box says 1000 because 1000 is what people buy. Odd counts like 636 and 1008 exist for the same reason in reverse: someone chose to print the honest number rather than break the piece proportions to hit a marketing figure. Gibsons uses 636 on its panoramas because a long, narrow rectangle needs a different grid to keep pieces a sensible shape.

Within that grid, there are three broad styles.

Two more things fall out of the pattern. The edge pieces are simply the ones the outer blade cuts flat on one side, and the four corners get two flat sides, which is why the frame is where everyone starts. And false fits, where a piece slides into the wrong hole and stays there, are a function of how much shape variety the pattern carries and how accurately it was cut. A precise die with plenty of variety gives you the satisfying click and very few false fits. That click is what Ravensburger trademarked as Softclick, and while the name is marketing the mechanism behind it is not.

The press, one stroke

The laminated sheet is fed into a heavy platen press, the die comes down, and every cut in the puzzle happens simultaneously.

The engineering problem is evenness. The force has to be distributed across the whole sheet so that a blade in one corner cuts to exactly the same depth as a blade in the centre. Too little pressure and parts of the sheet are only scored, so the pieces tear rather than separate. Too much and you crush the board at the cut, blunt the blades and shorten the life of a tool that cost a fortune. Presses are set up, tested against a sample, adjusted, and monitored, and dies are pulled periodically to be resharpened.

The blade has thickness, so every cut consumes a hairline of board. That is why an assembled puzzle is fractionally smaller than the printed sheet was, and why you can see the cut lines at all when it is finished.

Breaking, brushing and counting

Out of the press comes something that still looks like a complete picture. It has been cut all the way through, but the pieces are sitting exactly where they were made and friction is holding them there.

Breaking is the deliberate step of pushing them apart, either by machine or by hand. Then the pieces are brushed and vacuumed, because cutting board produces dust and small slivers, and that debris is what ends up in the bottom of a box and in the tabs.

Then they are mixed. Genuinely, deliberately mixed, because a puzzle that arrives in sorted order is not a puzzle.

Counting is generally done by weight rather than by hand. A bag of pieces from a known cut has a known mass, so a calibrated scale flags a bag that is a piece light far more reliably and far more cheaply than a person could. It is also the reason a maker can offer a missing piece replacement service and still sleep at night.

Bagging, boxing and the poster

The pieces are bagged, usually in one bag up to about 1000 pieces and in multiple bags above that. The box is assembled: a printed sheet wrapped onto board for the lid, and a base sized so the lid drops rather than jams.

Into the box goes the bag or bags, sometimes a poster of the finished image, and on the back of the box goes the piece count, the finished dimensions, the barcode and the toy safety marking. Then it is shrink wrapped and packed into cartons.

That poster is worth more than it looks. On large or low contrast puzzles, being able to lay a full size reference next to the build, instead of holding a lid at arm's length, changes the experience completely.

What all of this tells you at the shelf

The whole process reduces to a short list of things worth checking, and to an understanding of what you are paying for when a puzzle costs more.

Common questions