How to Make a Tech Pack for Denim Jeans: Step-by-Step Guide

A denim tech pack is a technical document that gives your factory every specification they need to manufacture your jeans accurately—from fabric weight and construction details to wash treatments, laser engraving patterns, and whisker placement. Without one, you're relying on verbal instructions and assumption, which is how sampling rounds multiply and margins shrink.

Denim is one of the most technically demanding categories in apparel. The fabric behaves differently after washing, finishing treatments alter dimensions, and details like rivets, bar tacks, and coin pocket placement have decades of industry convention behind them. A well-built denim tech pack accounts for all of it upfront—so your factory isn't guessing and you're not paying for corrections.

This guide walks you through every section of a jeans tech pack, in the order you should build it.

What Makes a Denim Tech Pack Different

Most tech pack guides cover the fundamentals: technical flat sketches, a bill of materials, a size spec sheet, and construction notes. Denim adds several layers of complexity that other garments don't have.

Wash and finish specifications are the biggest differentiator. Raw denim and finished denim are not the same product—enzymes, stones, bleach, and laser treatments all change how the fabric looks, feels, and measures. Your tech pack must specify what the garment looks like before washing (greige) and after, with tolerances for expected shrinkage.

Hardware is structural, not decorative. Rivets, shank buttons, and bar tacks in jeans carry real mechanical load. The wrong specification here isn't an aesthetic problem—it's a durability failure.

Whiskers and laser engraving are design elements that require precise placement maps. If your factory doesn't have an exact reference, these details become inconsistent from unit to unit.

Understanding these distinctions is what separates a denim tech pack that works from one that just looks complete.

Section 1: Cover Page and Style Information

Every tech pack starts with a cover page that gives the factory an at-a-glance summary of the style.

Include the following on your cover page:

• Brand name and logo

• Style name and style number (e.g., "Slim Straight Jean / SS26-DNM-001")

• Season and year (e.g., Spring/Summer 2026)

• Colour and colourway code (e.g., Indigo Wash / IND-01)

• Fabric description (e.g., 12oz Selvedge Denim, 98% Cotton 2% Elastane)

• Tech pack version number and date — critical for denim, where you may be on revision 4 by the time the wash is right

• Designer or brand contact

• Target factory (if known)

A clear version history table is especially important for denim. Wash development often runs in parallel with fit development, and you need both teams working from the same revision.

Section 2: Technical Flat Sketches

Your flat sketches are the visual foundation of the tech pack. For jeans, you need a minimum of four views:

1. Front flat — seams, pockets, fly, rivet and button placement, coin pocket position

2. Back flat — yoke shape, back pocket placement, patch label position, back rise seam

3. Detail views — waistband construction (inner and outer), fly construction (zip or button), belt loop spacing, pocket bag shape

4. Label placement diagram — main label, care label, size label, patch label (if applicable)

What to Show on the Front Flat

Mark every seam line clearly. For jeans, this includes the inseam, outseam, crotch seam, fly seam, and coin pocket. Show the zip or button fly open and closed if the construction detail warrants it.

Indicate rivet positions with a symbol and a callout. Indicate bar tack positions the same way—bar tacks on belt loop ends, pocket corners, and fly base are standard, but your placement may differ.

What to Show on the Back Flat

The back yoke is a defining element of any jean silhouette. Show its exact shape and angle—don't leave this to factory interpretation. Back pocket placement is equally defining: mark the distance from the waistband seam, from the outseam, and the angle of any embroidery or stitching detail.

Drawing Standards

You don't need to be a CAD expert. Platforms like Specter OS include a pre-loaded garment CAD library with base flat sketches for common silhouettes—including jeans—so you can annotate over an accurate base rather than building from scratch.

Section 3: Bill of Materials (BOM)

The bill of materials lists every component that goes into the garment. For denim jeans, this list is longer than most people expect.

Include colourfastness requirements and any restricted substance restrictions (REACH compliance, OEKO-TEX, etc.) in a notes column if relevant to your market.

Section 4: Fabric and Wash Specification

This is the section that makes or breaks a denim tech pack. Be precise.

Fabric Specification

• Weight: Specify in ounces per square yard (oz/sq yd). Lightweight denim is 8–10oz; mid-weight is 11–13oz; heavyweight is 14oz+.

• Composition: List fibre content exactly as it will appear on the care label.

• Weave: 3×1 right-hand twill is standard. Selvedge, left-hand twill, and broken twill are design decisions that must be stated explicitly.

• Stretch: For stretch denim, specify elongation percentage and recovery rate.

• Shrinkage tolerance: State expected warp and weft shrinkage after wash so patterns are cut to account for it.

Wash and Finish Specification

Denim wash development is a craft in itself. Your tech pack needs to describe the target finish in enough detail for a wash house to replicate it.

Include:

• Wash type (e.g., enzyme wash, stone wash, acid wash, bleach wash, or raw/unwashed)

• Target shade — provide a physical lab dip or Pantone Textile reference

• Hand feel target — soft, crisp, broken-in

• Any tinting or overdye — e.g., sulphur-dyed topcoat for vintage cast

• Before-wash vs. after-wash measurements — include a shrinkage spec for key dimensions (length, waist, inseam)

Section 5: Laser Engraving and Whisker Specification

Laser engraving and whiskers are the two denim-specific design details that most tech packs underdocument. Don't make that mistake.

Laser Engraving

Laser engraving uses a controlled laser to selectively fade denim, creating distressed effects, abraded patterns, or graphic elements without manual sanding. It's increasingly standard in mid-to-high-volume production because it's consistent and repeatable.

Your tech pack must include:

1. Laser artwork file — a greyscale bitmap or vector file where white = maximum fade, black = no fade. Your factory's laser technician works from this directly.

2. Placement diagram — show exactly where on the garment the laser is applied: front thigh, knee, back seat, or custom position. Measure from the waistband seam and from the inseam or outseam.

3. Intensity target — light, medium, or heavy fade. Provide a physical reference panel if possible; laser settings vary by machine.

4. Area dimensions — width and height of the laser panel in centimetres.

Without a placement diagram and artwork file, laser results will vary. Provide both.

Whiskers

Whiskers (also called "honeycombs" at the back of the knee) are the radiating crease lines at the top of the thigh that simulate natural wear. They're applied manually or via laser.

For manual whiskers:

• Provide a whisker pattern diagram showing the angle, number of lines, and origin point (typically the crotch seam)

• Specify whether whiskers are applied by hand-sanding, resin-setting, or laser

• Provide a reference image or approved lab sample

For laser whiskers, include a dedicated laser file in addition to any other laser artwork.

Whisker intensity should be specified as light, medium, or heavy, with a reference swatch. This is a finishing detail that is highly subjective—always approve a physical sample before bulk production.

Section 6: Construction and Sewing Specification

List your construction requirements in a dedicated section. For jeans, cover:

• Seam type per seam — felled seam (outseam and inseam is standard), plain seam with overlock, flat-felled

• Stitch type and SPI — stitches per inch. Topstitching on jeans is typically 7–8 SPI; construction seams 10–12 SPI

• Seam allowance — standard is 1cm finished

• Fly construction — zip fly or button fly, fly shield, bartack positions

• Waistband construction — width (finished), self or contrast lining, beltloop count and spacing (typically 5 or 7 loops), curtain or no curtain

• Pocket construction — front pocket depth, coin pocket position, back pocket placement and any embroidery detail

• Bar tack placement — list every position: belt loop tops and bottoms, pocket corners, fly base

• Rivet placement — mark on the flat sketch and list dimensions from seams

Hardware Specification

Specify every piece of hardware by:

• Type (shank button, rivet, hook-and-bar)

• Material (brass, antique brass, gunmetal, nickel-free)

• Size in millimetres

• Finish

• Supplier reference if you have one

Section 7: Size Specification Sheet (Measurement Chart)

The size spec sheet is where your graded measurements live. For a five-size run (26–34 or XS–XL), you'll need every key measurement for every size, with tolerances.

Key measurements for jeans:

Tolerances for jeans are typically ±0.5cm for body measurements and ±0.3cm for waistband and rise. State your tolerances explicitly.

For a deeper look at tech pack measurement pages, see our common tech pack mistakes guide—many of the most costly errors live in the spec sheet.

Section 8: Labelling and Packaging

Specify every label: position, attachment method, and fold type. For jeans:

• Main woven label — inside waistband centre back, folded mitre or straight

• Size label — attached to or below main label

• Care label — inside waistband left side, or inside left seam

• Patch label — outside back right waistband (if leather or woven patch), specify attachment: sewn all sides, sewn top and sides only, or riveted

• Hangtag — attachment point and method (pin, string, safety pin)

Include packaging requirements: folding method, poly bag size, sticker placement, carton specs for bulk shipment.

Managing Your Denim Tech Pack with Specter OS

A denim tech pack has more moving parts than almost any other garment category. Wash specs, laser files, whisker diagrams, hardware lists, and graded measurement charts all need to stay in sync—and when you're on revision 6 of a wash development, version control becomes critical.

Specter OS centralises the entire process: you build your tech pack inside the platform using its CAD library as a starting point, communicate directly with your factory from the same workspace, and track sampling feedback and revisions without losing documents across email threads. It's built for exactly this kind of multi-layer development workflow. Specter OS offers a free tier for early-stage brands, making it accessible whether you're developing your first jean or managing a full denim range.

Conclusion

A denim tech pack is not a simple document—it's a production blueprint that covers fabric science, wash chemistry, precision hardware, and finishing artistry simultaneously. Get it right, and your factory can hit the brief on the first or second sample. Get it wrong, and you'll spend months in correction cycles that eat into your margin and your launch window.

Build it section by section: cover page, flats, BOM, fabric and wash spec, laser and whisker detail, construction notes, size spec, and labelling. Each section answers a specific set of factory questions. When every question is answered on paper, the only thing left to do is sample.

If you're starting from scratch with tech packs in general, the how to make a tech pack guide is a solid foundation before you dive into denim-specific complexity.

Frequently Asked Questions

What is a denim tech pack? A denim tech pack is a technical specification document that contains everything a factory needs to manufacture a pair of jeans—including fabric weight, wash instructions, construction details, hardware specs, laser engraving files, whisker placement, and graded measurements. It is the single source of truth between a brand and its manufacturer.

How do I specify laser engraving in a tech pack? Laser engraving in a tech pack requires three things: a greyscale artwork file (white = maximum fade, black = no fade), a placement diagram showing exactly where on the garment the laser is applied with measurements from seams, and an intensity target (light, medium, or heavy). Where possible, provide a physical reference panel alongside the digital files.

What are whiskers in denim and how do I document them? Whiskers are the radiating crease lines at the top of the thigh that mimic natural wear patterns. In a tech pack, they're documented with a whisker pattern diagram showing line angle, count, and origin point, a specification of the application method (hand-sanding, resin-setting, or laser), and an intensity reference. Always approve whiskers on a physical sample before bulk production.

How many measurement points does a jeans tech pack need? A complete jeans size spec sheet typically includes 10–15 measurement points: waist, hip, front rise, back rise, thigh, knee, leg opening, inseam, outseam, and waistband width are the core set. Each measurement should include a tolerance (typically ±0.5cm for body measurements) and be graded across every size in the range.

Do I need a separate spec for before and after washing? Yes. Denim shrinks during washing, and your factory needs to know how much