Reducing colour change risks

Cleaners need all their craft skills to avoid colour changes and in some cases avoiding them completely is impossible but attention to three main points will minimise changes in most cases.

Moisture: Moisture has a strong tendency to cling to natural fibres such as cotton, linen and wool. Once this happens, the moist fibres become a “magnet” for every trace of particulate and dissolved soiling in the solvent. The soiling then re-deposits on the cloth, forming a layer one or two molecules thick, which makes the fabric look grey. This affects both pastels and whites.

Detergent: The detergent dose should be designed to disperse any free moisture and using the correct dose will prevent greying provided the moisture is not excessive. The detergent will also wrap itself around any soiling and physically hinder re-deposition, neutralising any electrical charge on the soiling in the process. Note that using too much detergent can be as dangerous as using too little because the detergent itself contains a trace of moisture to help remove water-based staining and soiling.

Distillation: To reduce the risk of greying, the machine must be programmed to distil sufficient solvent during every process to ensure an adequate supply. I recommend using working tank solvent for the first bath in every two-bath process and sending this to the still at the end of the stage. The second bath should then be drawn from the distilled tank, charged with detergent and sent to the working tank at the end of the stage. This method ensures that the final stage of every process uses distilled solvent and that there is enough detergent left in this to make sure that the working tank is also charged with detergent.

Pre-drying/airing of cottons, linens and wools, precise detergent dosage and good distillation practices are just three of the tools in the cleaner’s armoury. The case studies examine several types of colour change and explain how the risks can be minimised.

Blue hue in white trim

Fault: This blue and white jacket was cleaned in perc but the white took on a blue tint.

Cause: The colourfastness to drycleaning in a garment with contrasting colours is more critical than in a plain garment, which can be dealt with by classification. Here, even a very slight bleed of the blue dyes into the cleaning solvent will affect the white parts. The dyer can sometimes prevent the fault by improving the washing-off of the blue fabric or yarns after dyeing. It is not always necessary to use a more expensive dye recipe.

Responsibility: The garment maker and ultimately the original dyer should take the responsibility here. The cleaner could not have prevented the bleed and cannot correct it now.

Special treatment needed

Fault: This jacket had local smoke and carbon damage when it was brought in. During cleaning the marking spread producing an irremovable grey patch.

Cause: The cleaning solvent has lifted the carbon particles in the smoke away from the fabric but the detergent did not have enough suspension power so the soiling has re-deposited, producing the grey patch.

Responsibility: The cleaner is probably to blame here for making the marking worse rather than better. However, smoke damage cannot always be removed completely.

Rectification: Electromechanical forces have now bonded the carbon particles to the fabric and it is unlikely that the bond can be broken. Multiple re-cleaning will have no effect. For the future, the cleaner needs to use the maximum dose of a specially formulated “smoke-soap” with a very high suspending power.

Classify leather carefully

Fault: This yellow leather jacket looked slightly darker and had a brown tinge after it had been drycleaned.

Cause: Leather is usually direct dyed, so it is less colourfast than a fabric garment. The leather cleaner needs to classify garments very carefully. If a yellow jacket is cleaned with brown jackets it is often impossible to avoid some colour transfer via the solvent. This transfer does not mean that one of the brown jackets was faulty.

Responsibility: The cleaner generally takes responsibility for colour transfer caused by inaccurate classification and should do so in this case. If the jacket could not have been cleaned with a garment of a similar shade, it would have been wise to clean it on its own.

Rectification: This type of colour transfer is not generally reversible. The jacket should be left as it is.

Drycleaning removes optical brightener

Fault: This shirt was a bright white when it went into the drycleaning machine but looked drab and dull when it came out.

Cause: The original brightness was produced by applying an optical brightener (OBA) to the fabric during manufacture. The OBA would have reacted with the ultraviolet portion of natural daylight and converted this into brilliant white light, making the fabric look bright and lively – especially under disco lighting. Some inexpensive OBAs come off in drycleaning solvent with the drab result found here. The fault can be detected using an OBA meter of the type shown in the photograph.

Responsibility: The garment maker and ultimately the original cloth finisher are responsible here. It is possible to get OBAs that are durable.

Rectification: Gently hand washing the garment several times in a washing detergent containing OBA should cure the fault. There is a risk of slight shrinkage but this can be minimised in pressing and most wearers should tolerate this. This shirt was a bright white when it went into the drycleaning machine but looked drab and dull when it came out.

Trim fades during c leaning
Fault: This brown ribbon trim faded when the dress was cleaned in perc.

Cause: Garment makers usually check the colourfastness of the main dress fabric very carefully but they often forget to check the trim. The ribbon used here appeared to have been dyed by dipping in strong coffee, judging by the result of the trim’s colourfastness to wet and dry rubbing when tested with the crockmeter as shown here.

Responsibility: This garment was labelled for drycleaning in perc so the maker should take responsibility. The cleaner could not have foreseen the result.

Rectification: The best solution in this case is for the owner to return the garment to the retailer.