- How to Read the 11 CRT Content Areas
- Domains 1-2: Color History and Color Theory
- Domains 3-5: Dyes, Dye Methods, and Dye Types
- Domains 6-7: Fibers and Carpet Styles
- Domain 8: Dye Procedures
- Domains 9-11: Fading, Contamination, and Cleaning Agents
- Course, Exam Mechanics, and Fees
- Sequencing the Domains in Your Preparation
- Frequently Asked Questions
- The 11 domains are unweighted preparation-curriculum topics from IICRC's course description, not an official 11-section exam blueprint.
- CRT covers color correction and repair of nylon and wool textiles, so fiber identification underpins nearly every other domain.
- CCT or CCMT certification must come first; the published CRT course is two days and 14 instructional hours.
- The initial exam and each retest cost $80 USD, and the passing threshold is 75%.
How to Read the 11 CRT Content Areas
The Color Repair Technician (CRT) credential, governed by the Institute of Inspection Cleaning and Restoration Certification (IICRC), concerns the correction and repair of color on nylon and wool textiles. That includes restoring carpet shade, choosing a dyeing procedure, and repairing fabrics that were improperly dyed. The 11 domains in this guide come from the detailed topic list in IICRC's CRT course description.
IICRC has not published a CRT-specific question count or a timed-exam duration, so this guide does not quote one. For the complete credential picture, see our overview of what CRT certification is, and for a broader discussion of difficulty, see how hard the CRT exam is.
Domains 1-2: Color History and Color Theory
Domain 1: History of Color
The course opens with the background of how humans have produced and used color. This is the lightest domain conceptually, but it frames why dye chemistry evolved the way it did.
- Understand the progression from natural coloring sources to modern synthetic colorants.
- Connect historical developments to the dye classes you will meet later in the course.
- Expect recognition-style recall rather than calculation.
Domain 2: Color Theory
Color theory is the working vocabulary of the whole credential. Every correction decision, such as which dye to select and how to neutralize an unwanted tone, depends on how colors interact.
- Know how primary, secondary, and complementary relationships determine what a dye will do to an existing shade.
- Be able to reason about what happens when one color is applied over another.
- Understand why a repair that looks right under one light source can look wrong under another.
Spend real time here even though it sits early in the list. Candidates who treat color theory as background reading tend to struggle later when procedure questions require them to predict the outcome of a dye application. Our CRT study guide shows how to fold this domain into a full preparation plan.
Domains 3-5: Dyes, Dye Methods, and Dye Types
These three domains form the chemistry core of the course. They are related but distinct, and exam-style questions often test whether you can keep them apart.
Domain 3: Natural and Synthetic Dyes
This domain distinguishes colorants by origin and explains why the distinction matters in a restoration setting.
- Differentiate natural dyes from synthetic dyes by source and typical behavior.
- Understand why modern carpet manufacturing relies on synthetic chemistry.
- Know how origin influences stability, fastness, and response to cleaning.
Domain 4: Dye Methods
Dye methods describe how color gets into a textile in the first place, and therefore what a repair technician is trying to replicate or work around.
- Learn the manufacturing-side approaches to applying color to fiber.
- Recognize how the original dyeing method affects what can be corrected afterward.
- Understand why some color is deeply bonded and some sits closer to the surface.
Domain 5: Types of Dyes
This is where classification becomes practical. Different dye classes interact differently with fibers, and the correct choice of dye is central to a successful repair.
- Match dye classes to the fibers they bond with.
- Understand how dye type affects permanence and the ability to blend with existing color.
- Be ready to justify a dye selection, not merely name it.
Domains 6-7: Fibers and Carpet Styles
Because the credential is scoped to nylon and wool, these domains carry unusual weight in practice, even though the course description does not formally weight them.
Domain 6: Types of Fibers
Fiber identity determines which dyes bond, which chemicals are safe, and what a realistic repair outcome looks like.
- Know the characteristics of nylon and wool, the two textile families the credential concerns.
- Understand how each responds to dyes, bleaching agents, and cleaning chemistry.
- Be able to recognize when a fiber is outside the scope of a standard repair approach.
Domain 7: Carpet Styles
Construction and pile style affect how dye is applied and how a repair will blend visually.
- Recognize common carpet constructions and pile styles.
- Understand how pile height, density, and texture influence both application and appearance.
- Connect style to the practical challenge of making a repair invisible.
Many candidates already know these topics from the prerequisite credentials, since CCT or CCMT certification is required before CRT. Review them anyway, but through a color-repair lens: the question is no longer "how do I clean this?" but "how will this react to dye?" The CRT requirements guide covers the prerequisite path in more detail.
Domain 8: Dye Procedures
Domain 8: Dye Procedures
This is the hands-on heart of the credential, where theory becomes technique. The course description lists it as a single domain, but it is the one most directly tied to day-to-day repair work.
- Understand the sequence of steps in a controlled dye repair and why order matters.
- Know how to select a procedure based on the fiber, the damage, and the desired result.
- Be prepared for scenario questions that ask what to do next when conditions change.
Provider courses often teach this material through specific techniques. For example, LearnToRestore's CRT course describes dye kits, spot and room dyeing, shading and feathering, and bleach or chemical neutralization. Those are school-level topics that illustrate the domain; they are not additional official exam domains, so use them as practical context and not as a separate checklist.
Key Takeaway
When you study Domain 8, work backward from the problem: identify the fiber, identify the cause of the color problem, then choose the procedure. Exam scenarios reward that diagnostic order more than memorized step lists.
Domains 9-11: Fading, Contamination, and Cleaning Agents
The final three domains cover why color goes missing in the first place. Diagnosing the cause is the first half of every repair, and these domains train that diagnostic skill.
Domain 9: Fading
Fading is gradual color loss from environmental exposure, as opposed to a sudden chemical event.
- Understand the common drivers of fading and how they present across a carpeted area.
- Recognize patterns that point to exposure and not to a spill or product.
- Know what is and is not realistically correctable.
Domain 10: Color Loss Due to Contamination or Bleaching
This domain separates contamination-related color changes from deliberate or accidental bleaching, which often look similar but call for different responses.
- Learn to distinguish a contaminant's effect from a bleaching agent's effect.
- Understand how the cause of loss affects the repair approach.
- Be able to describe how an unwanted residue or reaction changes the underlying dye.
Domain 11: Use of Cleaning Agents That May Affect or Remove Color from Carpet
The closing domain turns the lens on the technician's own toolkit. Some cleaning products can alter or strip color, so knowing which is essential to avoiding self-inflicted damage.
- Identify categories of cleaning agents with the potential to affect carpet color.
- Understand why fiber type changes the risk profile of a given agent.
- Connect product selection to the prevention of avoidable color complaints.
Course, Exam Mechanics, and Fees
Knowing the domains is only part of the picture. The administrative rules below come from IICRC's published sources and are worth confirming directly with IICRC before you schedule.
| Item | What IICRC Publishes |
|---|---|
| Prerequisite | CCT or CCMT certification before CRT |
| Course length | Two days, 14 instructional hours (excluding exam time, lunch, and breaks) |
| Formats | Live-stream and in-person |
| Initial exam fee | $80 USD (tuition is separate unless a school bundles it) |
| Each retest | $80 USD |
| Passing threshold | 75% |
| Live-stream exam window | Complete the online exam within 45 days after the final course date |
| In-person exam | Written exam on the final course day |
Retest rules to know in advance
After an initial failure, candidates may retest up to two times. A second failed retest requires re-enrolling in the course. For retest timing, IICRC's detailed retest page gives 45 days from the scoring date of the preceding exam, with a new 45-day period beginning after the first retest is scored. IICRC's general FAQs word this differently, referring to the exam date, so confirm your assigned deadline with IICRC rather than relying on either phrasing alone.
The 45-day figure for live-stream candidates is a completion window, not the length of the exam itself. For full detail on costs, see the CRT certification cost breakdown; for score specifics, see what you need to pass; and for timing, see the CRT exam dates guide.
Maintaining the credential
Technician credentials require annual renewal and 14 continuing education credit hours every four years. Master and Inspector holders follow a separate 14-hour, two-year requirement. Renewal charges vary with the number and type of credentials held. CRT is also required for the Master Textile Cleaner pathway, but it is not sufficient by itself, so it is best viewed as one step on a longer route. If you are weighing that route, our analysis of whether CRT is worth it and the CRT salary guide can help frame the decision.
Sequencing the Domains in Your Preparation
Because the domains are unweighted, there is no official reason to spend more time on one than another. There is, however, a logical dependency order. Fibers and color theory feed everything else, so schedule them first. The timeline below assumes a short preparation window around the two-day course; adjust it to your own calendar.
Foundations
- Review Domain 2 (color theory) and Domain 6 (types of fibers) first, since later domains depend on them.
- Skim Domain 1 (history of color) for context.
Dye Chemistry
- Work through Domains 3, 4, and 5 together, but keep methods and types in separate notes.
- Add Domain 7 (carpet styles) and relate each style to dye behavior.
Procedures and Diagnosis
- Study Domain 8 (dye procedures) using problem-first scenarios.
- Cover Domains 9, 10, and 11 as a single diagnostic set: fading, contamination or bleaching, and cleaning agents.
- Take timed practice questions on the CRT practice test site to check retention.
For a compact last-day review, the CRT cheat sheet condenses the must-know facts, and the main practice test is a good way to find weak domains before the exam. Candidates who want broader context on expectations can also read the CRT pass rate discussion, which explains why published figures should be treated cautiously.
Key Takeaway
Prepare around the cause-and-fix logic that connects the domains: identify the fiber, diagnose why color was lost, then select the dye and procedure. If you can walk through that chain out loud for a sample problem, you are studying the right way.
Frequently Asked Questions
No. They are the detailed preparation topics named in IICRC's CRT course description. IICRC does not publish them as a weighted examination blueprint, so no domain has a verified percentage of the exam.
CCT or CCMT certification is required first. After that, you complete approved CRT instruction and then the exam. See the CRT requirements guide for the full path.
The initial exam and each retest cost $80 USD. Course tuition is separate unless the school explicitly bundles it. The pricing breakdown covers the details.
IICRC's retest FAQs give a 75% passing threshold. A candidate may retest twice after an initial failure; a second failed retest requires re-enrolling in the course.
No. The credential concerns color correction and repair of nylon and wool textiles specifically, which is why Domain 6 on fiber types is so central to the rest of the material.