Don’t turn one headache into another
(and how to avoid it)


Do you experience issues with bulk shade variations? You are not alone.

To reduce the problem of bulk shade variations, some mills use VAT dyes to match color standards made with reactive dye. 

The main reason for a dyer to use VAT dyes is foremost the good fastness properties (wet fastness, light fastness...) and to have shade stability to flame retardant after-treatments.

All good to go? 
Not if you don’t want metamerism (when two colors match under one light source, but not another). For some colors, such as beige, olive, and khaki, metamerism will appear when using VAT dyes. This means that your khaki colored lab dips likely will flare under the second illuminant.

Products in the risk zone
VAT dyes are mostly used on woven cotton or polyester cotton fabrics. The end-usage is often workwear and protective wear, uniforms, hospital, and toweling.

Do you want good fastness performance and metameric free?
One can use a color standard that is dyed with VAT dyes to solve the issue (but there is no VAT dyed color standards…). So, this is what to do to get metameric free VAT recipes for a color standard that is dyed with reactive dyes:

In most cases you need to choose VAT dye combinations that have poor reproducibility.
 
If metamerism AND reproducibility is important: DO NOT use VAT dyes.

For beige, olive, and khaki colors one can make recipes with very good reproducibility with the following dye combination:
C. I. V OR 11 (Novasol Yellow 3R – Huntsman)
C. I. V BR 1    (Novasol Brown BR – Huntsman)
C. I. V BK 25  (Novasol Olive S - Huntsman)
 
If a brand requires VAT dyed fabric to reach a special fastness performance, then the color should be matched under the primary illuminant. The labdip should be sent to the retailer and if approved it will be the standard for production.

For you color tech geeks, click here to get the following recipes:
- Reactive recipe
- VAT recipe with outstanding reproducibility, but metameric
- VAT recipe with reproducibility issues, but no metamerism


Do you want to meet your color and quality goals? If YES, email our support team at support@natific.com and we will get back to you. It doesn’t matter if you are a colorist at a dye house, a vendor or part of a brand’s production team.

Did you find this article interesting? Then you will probably love this: How to control and improve your color range

                    


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