Carpet sidematch or carpet side match is the appearance of a shade or hue variation between joined carpet panels. The eye may see what appears as two shades of carpet joined side-by-side. In actuality the shades may be identical.
Carpet is a manmade product that goes through many processes from yarn production, to manufacturing into carpet and its final installation.
During manufacturing a dye or texture variation may occur, resulting in a sidematch appearance variation. During seaming and installation of carpet a real or perceived carpet sidematch appearance variation may also occur.
Color Vision and Carpet Sidematch
Not everyone sees an object or light source the same way. An organism or machine will distinguish objects based on the wavelengths (or frequencies) of the light they reflect, emit, or transmit, this is known as color vision.
A person’s perception of colors is a subjective process. The human brain responds to the stimuli that are produced when incoming light reacts with the cone cells in the eye.
With a carpet sidematch, what the eye sees as a color variation may be an actual difference in hue, shadows, texture or other cause perceived as a color variation.
Manufacturing Sidematch Defect or Characteristic?
A carpet sidematch condition created during manufacturing is not necessarily a defect. A few examples are:
- Random sheared carpet products where more shearing will take place in some areas than it does in others.
- Random patterns, not designed for a perfect pattern match.
- Natural variations in color that take place between dye lots.
- Slight texture variations from one side of a roll to the other.
Each of these characteristics may give the appearance of a carpet sidematch. The end user pay perceive these as defects, while the carpet manufacturer recognizes them as characteristics.
Carpet sidematch variations are common. Visit model homes, particularly those that have large rooms and pay close attention to the seam areas. You will likely see many sidematch variations.
What Causes Carpet Sidematch Variation
Often, the end user, installer and dealer may all have different ideas as to why it is there. In fact a perceived difference may have multiple contributing causes.
- Pile reversed during manufacturing or installation.
- More light or shadow is being cast on one side of the seam.
- The seam excessively peaked.
- Multiple dye lots installed.
- The carpets texture may differ from one part of the roll to another.
- The pile may have a side-to-side or end-to-end color variation.
- Crushed pile on one side of the seam.
- The consumer’s expectations may be too great.
Who’s Fault is a Carpet Sidematch?
Carpet sidematch is a controversial claim. The consumer sees a defective product or installation while the manufacturer may disagree. The cause can be difficult to identify. Experts like the Weinheimer Group, realize both money and reputation are at stake. Care must be taken in determining the cause and if and how it can be corrected.
Cause and Effect
A carpet sidematch appearance difference taking place within the roll is not easily detectable until the carpet has been cut and placed side-by-side. Therefore it is routinely not found until the time of installation. What appears as the fault of an installer may actually be a manufacturing concern and the opposite is also true.
Peaking
- Seam peaking occurs during installation due to the flexing of the thermal plastic tape. Seam peaking is installation characteristic it is not an installation defect unless it is excessive and caused by improper installation.
- When carpet is stretched properly tight the peak may be higher.
- With a seam that runs across a major light source the peak will be more visible.
- When a seam runs into a major light source the peak will be less visible.
- In a large and sparsely furnished room, the peak may be more visible.
Pile Reversal
- Pile Reversal occasionally occurs during manufacturing. If the pile reverses midway along the panel and has been there since installation, this will normally be a manufacturer related pile reversal.
- Sometimes you find that in the lengthwise direction the sweep is the same and in the widthwise direction it reverses. This condition is unusual and is easiest to identify when all of the arrows on both sides of both panels run in the same direction but you find a side-to-side sweep that is different.
- Pile reversal more commonly occurs during installation. Pile direction testing and printing on the back of the carpet can usually determine when it occurred
Lighting
- Lighting is a site-related condition that plays a big roll when it comes to seam visibility. Some rooms have low windows, others high, wall to wall, or floor to ceiling.
- Some structures are designed with most artificial light at one end or side of the room. Light may be overhead in one area and tabletop lighting in another. Some layouts are such that the seams cannot be ran into the major light source to reduce seam visibility. Under many lighting conditions no matter what you do, a sidematch difference is going to be seen.
Proper Planning
- Proper planning for installation can play a big part in seam visibility. Taking fill pieces from the same side of the roll and in sequence to its joining panel will reduce variations.
- When multiple rolls of carpet are cut in dye-lot series, sidematch problems are normally reduced.
Color
- Hue or shade difference within the roll can occur during manufacturing. Many manufacturers as measured by the AATCC Gray Scale consider a 3.5 to 5 percent variation normal. When carpet is manufactured with nylon pile a hue condition can often be corrected, using a dye process called feather blending. This process is permanent and does not affect the performance of a carpet.
Industry Standards
CRI Carpet Standard 105 – 2015 states, With any seaming method, a properly constructed seam:
- has cleanly trimmed edges properly secured with edge/seam sealer
- has tightly abutted edges without gaps or overlaps
- maintains reasonable pattern match where applicable
- will not be invisible
Onsite Inspection of Carpet Sidematch Variations
Some sidematch variations are correctable and others are not.
- Some sidematch variation require little more than direct steam to reorient the pile.
- With an actual hue difference, some sidematch condition are correctable by a feather blending process.
- Other installation may require a partial of full replacement to correct.
Often an onsite inspection is required to determine the best course of action. Certified carpet inspectors are available throughout the United States. Among the best known and highest respected inspection companies, are The Weinheimer Group, nationally recognized certified carpet inspectors serving the states of Oregon and Washington and available for travel to other areas.

Recently i bought carpet that was in all appearances in the sample book, name and product number reasonably close to the same carpet we boutght 5 years ago.. However, the carpet manufacturer had in fact mad a major change in dye using a grey rather than a tan basic background. The carpets do not match. They say it is an allowable dye lot variation. I say no. Allowing for fiber and dye lots variations seems to me to be more under control with modern fibers and chemistry.
James
Most carpet manufacturers find that a given production can be within 10% heavier in shade than the manufacturer’s standard, and another production run of that same style/color carpet be within 10% lighter in shade than the manufacturer’s standard and both still be well within the acceptable range of dye lot variation, even if the actual difference in shade between the two productions could be as great as near 20%! This is why it is imperative to know that (dye lot) shade variations are not validated based on comparisons to the dealer’s showroom sample or from roll to roll, but rather from roll to the manufacturer’s standard.
Have you ever used a shadow box when taking pictures of a suspect side match defect ?
Yes. A shadow box works well as it blocks out any side lighting.
How does one execute the ‘feather blinding process’?
Thanks for the help
Feather blending is a process where the shade on the dark side of the carpet is matched and carefully feathered into the lighter side. Correctly done, it becomes difficult for the human eye to notice the difference in shade between the joined panels of carpet.
Who are you trying to convince? The same lot should look the same. Recently I had this problem and the company tore out the mess and did the job again.
Often carpets are replaced when there is a sidematch problem. Not all fibers are correctable by blending, on some the match is too far off. There are many reasons carpets are sometimes replaced when there is a sidematch shade, hue or texture variation.