Lab Dips and Strike-Offs for Underwear: Approval Steps That Prevent Delays

Answer first: A lab dip approves a dyed textile shade; a strike-off approves printed artwork on the intended substrate. They answer different questions, and neither should be approved from an uncalibrated phone photo. A controlled approval process links the color standard, material, light source, comments, revision number and bulk tolerance before production begins.

Use the right approval for the right process

Lab dips are commonly used for piece-dyed fabric, yarn or elastic. Strike-offs are used for screen, rotary, digital or transfer prints. A printed waistband may require a strike-off even when the body fabric uses a lab dip.

State the process and substrate in the request so the supplier does not send the wrong type of sample.

Start with a controlled color standard

Provide a physical swatch, recognized color reference or approved digital target with clear limitations. A brand color copied from a website is not a production standard because screens, profiles and ambient light vary.

Record the standard ID, material and date. If the standard changes, open a new approval round rather than editing the old comment chain.

Request numbered options, not anonymous swatches

Suppliers often submit several lab-dip options around the target. Each option should have a unique code. Comments such as “less red than option B” are useful only if everyone can identify the same B.

Keep the submission card with the chosen swatch. The approval is evidence for bulk inspection.

Evaluate shade under defined lighting

A color can match under daylight and shift under store or office lighting. Review under the light sources relevant to the market and record them. Also place body fabric beside the waistband, label and print because different fibers reflect light differently.

If metamerism is unacceptable, define that before bulk rather than after garments are packed.

Check strike-offs for more than color

A strike-off also proves artwork scale, repeat, registration, line sharpness, coverage, handfeel and interaction with stretch. Pulling a printed underwear panel can reveal cracking or loss of opacity that is invisible when the sample lies flat.

Approve the actual production artwork and substrate. A strike-off on a convenient substitute fabric is only a development reference.

Write comments that the dye house can act on

Avoid “not right” or “make it better.” State the direction and degree: slightly darker, less yellow, cleaner blue or closer to the approved standard under a named light source.

One consolidated comment from the brand prevents contradictory instructions from design, merchandising and quality teams.

Define the path from approval to bulk

The approval should state whether it is final, conditionally approved or rejected. Conditional approval needs an objective condition. Bulk fabric should then be checked against the retained standard within the agreed shade tolerance.

Approval of a small sample does not waive testing for colorfastness, shrinkage or print durability.

Protect the calendar with decision deadlines

Build submission, courier, review and revision time into the critical path. Multiple rounds can delay fabric booking and every downstream sample.

Send complete color information with the product brief to your underwear manufacturing partner. The manufacturing guide places color approval within the full sample-to-bulk sequence.

Buyer checklist

Frequently asked questions

What is the difference between a lab dip and a strike-off?

A lab dip is a small dyed-material submission for shade approval. A strike-off is a printed-material submission used to approve artwork color, scale, registration and print behavior.

Can a buyer approve color from a photo?

A photo can support discussion, but it is not a reliable final standard because lighting, cameras and displays alter color. Final approval should use a controlled physical or properly managed digital process.

How many lab-dip rounds are normal?

There is no universal number. Clear standards and actionable comments often reduce rounds; difficult fibers, fluorescent shades and cross-material matching may need more work.

Does lab-dip approval replace colorfastness testing?

No. Shade approval confirms appearance. Colorfastness testing evaluates resistance to washing, rubbing, perspiration or other specified exposures.