Matching jewellery sets — a pendant with earrings, a bracelet with a ring — need the same design at different sizes. A traced copy reproduces a design exactly, but an earring at pendant scale is often too large and heavy to wear, and a pendant at earring scale looks insignificant. Jewellery designers solve this at the drawing table with a fast grid technique that enlarges or reduces a design while keeping its proportions exact.
Why proportion matters more than size
The problem with naive scaling is distortion: stretch a design in one direction and the piece stops looking like itself. The hand method below keeps the length-to-width ratio constant, because everything is governed by one diagonal line. A photocopier will enlarge instantly, but the grid method needs no equipment and no queue — useful when a deadline is close.
The diagonal-grid method, step by step
- Draw the design at actual size. Sketch the piece in HB pencil, focusing on the outline and negative spaces first and leaving details for later. Ink the outline for sharp definition.
- Box the outline. With a ruler or triangle template, draw a box tightly around the outline at its exact length and width. Add a diagonal from the lower-left corner to the upper-right corner — this is the most important line in the whole process.
- Divide into quarters. By eye, draw a vertical centre line; where it crosses the diagonal, draw a horizontal line. You now have four sections.
- Divide again into sixteenths. Repeat the halving inside each quarter. Each time a vertical line meets the diagonal is where the next horizontal goes. Perfect measurement is not necessary — each section should just look equal to the eye.
- Set the new size on the diagonal. Extend the diagonal line by a few centimetres and extend the left vertical of the box upward. Decide the new size, draw the new top of the box parallel to the bottom until it meets the extended diagonal, and drop a vertical down from that meeting point. The new box is larger (or smaller) but has exactly the same length-to-width ratio as the original, because the diagonal never changed.
- Transfer the grid. Trace the new box and its diagonal onto tracing paper and divide it into sixteen sections the same way.
- Transfer the design point by point. Mark five or so points where the outline crosses grid lines in the small box, locate the same positions in the large box, and connect them with a smooth pencil line. Ink the final outline.
Combining scale with variation
Enlargement and reduction multiply the value of tracing techniques: trace to vary a design, then scale it to build an entire line — pendant, earrings, bracelet — from one accepted theme. The same design language appears at every scale, which is exactly what makes a set read as a set.
Scale also interacts with weight and wearability. A design that works as a pendant can be unwearable as an earring not because of its shape but because of its mass, so the reduced member of a set is often the one that gets worn most. Deciding pendant-versus-earring scale is a design decision, not an afterthought.
Where this is taught
The grid method comes from the drawing module of JDMIS Creative Drawing and Essential Jewellery Knowledge (JD100), where students practise enlarging and reducing their own traced designs into matching sets. It sits alongside top and side view drawing and estimating gem weight in a drawing as core hand skills.
Frequently asked questions
Why draw a diagonal line across the box?
The diagonal fixes the length-to-width ratio. Any box whose corner stays on that same diagonal — larger or smaller — keeps the exact proportions of the original design, so enlarging along the diagonal cannot distort the shape.
Do the grid sections have to be measured precisely?
No. The divisions are drawn by eye; the guide is that each of the sixteen sections should look as close as possible in size and shape. Precision comes from transferring the outline points at the grid crossings, not from measuring the grid itself.
How many points should I transfer between grids?
Around five well-chosen points where the outline crosses grid lines are enough to reconstruct the design accurately in the new box. Connect them with a smooth light pencil line, adjust, then ink.
When should a set member be reduced rather than kept the same size?
When wearability demands it: an earring copied at pendant size is commonly too large and heavy, while a pendant shrunk to earring size looks insignificant. Matching a set is about matching the design language at scales that suit how each piece is worn.