A tech pack is the single document that stands between your vision and what actually ships. It is your instruction manual for the factory — and if it's vague, incomplete, or missing key information, your manufacturer will make assumptions. Factories are efficient: they will not wait for you to clarify. They will guess, produce, and ship. The cost of those guesses lands entirely with you.
Most new brand founders send a PDF of their design artwork and call it a tech pack. That document tells the factory what the graphic looks like. It tells them nothing about the garment construction, the measurements, the fabric, the labels, the seams, the placement tolerances, or the finishing requirements. Every one of those gaps is a decision your factory will make without you.
"The factory didn't misunderstand. The factory made a decision. You just weren't the one who made it."
The 7 Sections Every T-Shirt Tech Pack Needs
Flat sketch — front and back. A clean line drawing of the garment, not a rendered mockup. The sketch should callout every construction detail: neckband type, sleeve attachment, side seam, hem finish, label placement. Use Adobe Illustrator or even a clean Figma file. Photography of a physical sample is not a flat sketch.
Size grading chart with tolerances. Measurements in centimetres for every size you're producing — chest width, body length, sleeve length, shoulder width, neck width. Include a tolerance column: ±0.5 cm for critical measurements, ±1 cm for secondary ones. Without tolerances, your factory will use their own standard, which may differ from yours by 2–3 cm.
Fabric specification. GSM, fibre composition (e.g. 100% combed ring-spun cotton), knit structure (jersey), and finishing requirements (pre-shrunk, enzyme washed). Reference the mill certificate if you've specified a particular fabric supplier. Do not write "soft cotton" — that means nothing to a production team.
Colour standard. Pantone TPX or TPG code for every colour in your range. Never send a CMYK or RGB value — those are screen colours, not fabric colours. If you're doing multiple colourways, each colourway needs its own Pantone reference. Colour accuracy in production is impossible without a physical standard.
Print placement diagram. Show where every graphic sits on the garment, measured in centimetres from fixed reference points: distance from the collar seam, from the side seam, from the hem. "Centred on chest" is not a placement spec — it's a starting point for guesswork. Give an exact measurement and a tolerance (e.g. ±0.5 cm).
Labelling and branding details. Woven label dimensions and placement (usually centre back, 1.5 cm below collar seam). Care label content and placement (left side seam, 10 cm from hem). Size label placement. Hangtag attachment point. If you're doing a tearaway label, specify the perforation type. This section is almost always missing from first-time tech packs.
Seam and construction specs. Specify the seam type for every seam: single-needle, twin-needle, flatlock, or chain stitch. Stitch count per inch (SPI): 12–14 SPI is standard for jersey; 8–10 SPI is for heavy materials. Thread colour and reference number. If the shoulder seam needs a tape, say so and specify the tape width.
The Five Mistakes That Kill First Runs
Sending artwork files instead of a tech pack. Your .AI or .PSD file tells the factory what to print, nothing else. Without construction specs, they will build to their house standard — which may not match your silhouette at all.
Using RGB or HEX colour codes. Screen colours and dyed fabric colours are completely different systems. A navy HEX code will produce three different blues at three different factories. Pantone codes exist for exactly this reason — use them.
Missing the size grading chart. Without explicit measurements per size, factories will apply their own grading increments between sizes. Their S/M/L may be 3 cm increments; yours might need to be 2 cm. The result is a size range that doesn't fit the way you intended.
Not specifying thread colour. Factories default to their most common thread stock. If your navy t-shirt is stitched with mid-grey thread because you didn't specify navy thread, that's a remade order — at your expense.
Skipping the labelling section entirely. Factories will either skip labels or place them wherever their pattern cutter is used to placing them. Woven label positioning is a brand detail that consumers notice. Specify it — down to the centimetre.
The Review Process Before You Send
Before sending your tech pack to a factory, do one review pass specifically looking for anything you've described in words rather than numbers. Every word-based description is a potential misinterpretation:
"Oversized fit" → change to exact measurements at chest, waist, hip, length
"Soft fabric" → change to GSM, fibre type, finishing spec
"Centred graphic" → change to X cm from collar seam, measured to top edge of print
"Standard navy" → change to Pantone 19-3832 TPX
"Regular seam" → change to twin-needle coverstitch, 12 SPI, matching thread
Have someone who has never seen the garment read your tech pack and describe what they would produce from it. Every detail they get wrong or have to guess is a gap you need to close before the factory sees it.