Color bleed on NYLON is practically impossible, that is unless the dye process was flawed.
Nylon fiber is dyed with one of three methods.
Method 1, the dye is introduced to clear fiber called greige goods in a vat of hot dye. The clear fiber picks up the dye in microscopic dye sites. This method is less costly, produces a wider variety of color choice options, and is less stable color since the color is introduced to the exterior surface of the fiber. This is the most common method for dying nylon.
Method 2, the dye is included in the batch of nylon before it is extruded. Thus the extruded fiber contains the color inside the fiber. This method is more costly, produces fewer color choice options, and has the most stable color since the color is within the fiber.
Method 3, the dye is printed onto the woven carpet or rug, much like an inkjet printer squirts dye onto a piece of paper. This method makes it possible to create an infinite variety of design options and color choices, and is less stable color since the color is introduced to the exterior surface of the fiber.
ALL OF THE PROPER METHODS listed above for dying nylon would NOT PERMIT color loss or color shift using a near-neutral pH detergent such as Releasit. So how did color migration occur? It would appear that the manufacturer has obviously added additional red dye to the fiber after it was manufactured to add more sizzle or pop from the vibrant red color. This would account for its inability to retain red.
On a side note, red is the least stable color in the color spectrum, so it is always the one that's most likely to bleed first. This brings up an important point --- always test for color fastness whenever there's even a remote chance it might bleed (i.e. bright reds). And as David mentioned above, "Dye Lock" works great to prevent bleeding.
P.S. Many rugs are imported from India, Pakistan, Turkey, Iraq, Iran, Afghanistan, and throughout Asia. Many of the rugs that are exported from these countries are put together by poor peasants in sweat-shops. So it's impossible to know exactly how they may have dyed a piece. How did they dye it? What dyes were used?. They could have dyed the piece with beet juice for all we know. So once again, this underscores the need to test for color fastness first (even if we assume there won't be a problem).
Rick Gelinas
rick@excellent-supply.com