How to make a tech pack

To make a tech pack, settle every decision about the garment first, then write each one on the page where a factory will look for it: flats, construction, seams, a base-size spec, a bill of materials, labels, colourways, grade rules and a revision log. The order matters more than the software. Most packs that come back as a list of questions were not badly drawn. They were started before the decisions were made.

This is the sequence I follow on one style. If you want to know what each sheet is for first, What is a tech pack? covers that. Here the question is how to get from a sketch to pages a workroom can keep.

Before the first page, make the decisions

A tech pack records decisions. It cannot make them for you. Before drawing anything clean, write down the answers a factory will need, even roughly.

• Fabric. The body fabric, its weight and composition, and anything cut on the bias or backed with interlining.
• Base size. The one size you will sample and measure. Every other size is graded from it.
• Size run. Which sizes you will sell, for example XS to XL, so the grade rules have a start and an end.
• Closures. Buttons, zip or hooks, and how many. “A few buttons” is not yet a decision.
• Finishing. How hems, seams and edges are finished, inside and out.
• Colourways. How many, and which parts change colour with them.

If one of these is still open, the pack will show it, usually as a soft note that the factory reads one way while you meant another. A 3D sample is a good place to close the visual decisions, such as proportion, hem length and collar size, before they are written down. Moving a hem on screen takes minutes. Moving it after the spec is measured means changing three sheets.

1. Draw the flats, front and back

Flats are the reference every other sheet points back to. Draw the front and back to proportion, laid flat, with no figure inside and no shading. Every seam line, dart, topstitch and pocket opening should be visible, because a line that is not drawn will not be sewn.

Draw them once, carefully, and use the same flats on every page. If the collar on the construction sheet is a little wider than the collar on the lead sheet, the factory has to choose one. Where the full flat is too small to read, add a close-up: a collar stand, a cuff, a placket. A callout takes a few minutes to draw. A misread placket costs a sample.

2. Write how it is built

Construction notes describe how the garment goes together, in roughly the order a machinist meets it. Name the seam type and the stitch, the seam allowance, what is interfaced, how the facing is attached and how each edge is finished.

Write methods, not preferences. “Clean finish” means something different in every workroom. “Seam allowances overlocked together, pressed to the back, 1 cm” means one thing. Put each note beside the part of the flat it describes, with a line to it. Twenty numbered notes at the foot of a page, with no arrows, will be read in order, and one of them will end up on the wrong seam.

3. Measure the base size

The specification sheet lists the points of measure for your base size: bust, waist, hem, centre back length, shoulder, sleeve length, cuff opening, and whatever else defines the shape. Each point needs a name, a number and a diagram showing exactly where it is taken. Add a tolerance, the amount a finished garment can vary and still pass, so the factory knows what close enough means.

Measure the garment as designed, not the body that will wear it. If you have an approved 3D sample, the measurements can be read from it. If you only have a sketch, this is the step where it stops being a picture and becomes a size.

4. List every material

The bill of materials, or BOM, has a line for everything that goes into the garment: body fabric, lining, interlining, thread, buttons, zip, labels. For each line, give a description, the supplier reference if you have one, the colour, the size, the quantity per garment and where it goes.

Six 15 mm buttons in the body colour, on the centre front, is a line a factory can buy from. “Buttons” is not.

5. Place labels and set colourways

Show where each label sits and how it is attached: the brand label at the centre back neck, the care label in the left side seam, the size label beside the brand label or folded into it. Then build the colourway sheet. List each colourway and, for every part of the garment, the material and colour it uses.

Thread and buttons are the usual misses. A navy shirt with navy buttons and an ecru shirt with navy buttons is a choice. If the sheet does not say it, the factory makes the choice for you.

6. Write the grade rules

Grade rules tell a factory how the base size changes across the size run. Write them against the same points of measure as the spec, as the base measurement plus the step to the next size: bust 92 cm in M, 4 cm per size up or down. A pattern maker can grade from that. Without it, the factory either asks or invents its own step, and the L comes back fitting like someone else’s L. What is pattern grading? goes through this sheet in detail.

7. Date it and keep a revision log

Put a date and a version on every page, and keep a short log of what changed: hem lowered 2 cm, buttons changed from horn to corozo, care label moved to the right side seam. It is the least interesting sheet to make and the one that saves the most time. A factory working from an older PDF has no other way to know it is older.

Read it the way a factory will

Before sending, go through the pack sheet by sheet as the workroom would, and ask the questions they would otherwise send back.

• Can every piece be cut from what is here?
• Can every material be bought from the BOM alone?
• Is every seam described, and does each note point to a place on the flat?
• Do the flats match on every page?
• Does each colourway say what changes, down to thread and buttons?
• Do the grade rules cover every size you plan to sell?

I read a pack again the day after writing it. The gaps show up quickly once you are no longer the person who already knows the answers.

What to leave out

A pack does not need mood boards, fabric stories or the reasons behind the design. The factory needs to know what the garment is, not why. It also helps to say plainly what is not included. If the pack carries grade rules but not graded patterns, write that on the grade sheet, so nobody waits for files that were never coming.