Fading of Dyes Versus Pigments
A discussion of why dyes fade, advances in dye technology, and the implications for finishing techniques. April 19, 2006
Question
We are eyeballing using dye toners in our precat lacquer finishes. We've been using either plain old stain on the wood and sometimes using a pigmented shading additive. After fiddling with dye toner we prefer the look much more than shading additive, but we've heard some about fade. I'd really hate for a customer to call me back in a year or so and say that the finished panel on the side of the wall cabinet by sink window has faded to a color lighter than the rest of the kitchen. Is this a real concern? Is it pronounced, or does it take many years to happen?
Forum Responses
(Finishing Forum)
From Paul Snyder, forum technical advisor:
It will fade some over time. But I use dye toners a lot and have never had a customer come back with a complaint. The change happens slowly and isn't terribly dramatic so most people never even notice (except finishers). If a cabinet or piece of furniture is exposed to direct sunlight (near a window), it's going to fade in time no matter what you use.
From contributor A:
Many dyes today are being made from micronized pigments rather then the synthetic anilines. These dyes are better then the older dyes as far as fading goes because particles are actually blockers, but they too will fade if left in direct sunlight.
From contributor B:
The furniture industry has been using dyes for many years and the new dyes are very good at resisting fading. I've been using them for about five years and never had a problem. Also, dyes are impressive when they aren't used just for toning.
From contributor C:
All colors achieved using strictly all aniline dyes will fade, whether it is on fabric, leather, or wood. Most manufacturers use dyes more frequently in the pre-staining or NGR application in the finishing processes. They will usually apply a pigmented wiping stain or glaze as a second color application. Using pigments over dyes will minimize fading. Using dyes in lacquers or precatalyzed topcoats to shift the color in a big way at the end of the finishing process will put the color stability of the finish at risk. Slight color adjustments with dyes in topcoats at the end of the finishing process will be less obvious. It depends on the amount/intensity of the UV exposure as to how long it takes to fade color. Normal exposure will usually start fading aniline dye finishes within 3 months.
From contributor A:
To contributor C: I agree with your comments. So the readers do not get confused, I would like to add that the manufacturers do not add pigmented stains or glazes to prevent fading, they add these color mediums to increase the beauty and character of the finish.
From contributor C:
To contributor A: Using dye stains early in the finishing process provide clarity, brilliant color hues, as well as equalize to offer some uniformity to the existing wood specie color. Dye stains may also be known as, pre-stains, equalizer stains, sap stains, and NGR stains. Applying pigmented wiping stains and glazes over the top of a dye application with a washcoat sandwiched between will bring more color value, and depth to enhance a finish by accentuating the existing grain patterns and wiping cleaner off the flake. They serve as an aide to dial in closer to a desired color target. However, when using these pigmented materials you also gain some UV protection or "blocking" to the dyes beneath them. Manufacturers keep all this in mind to produce quality finishes. Many will test their systems extensively, especially those in the office furniture and kitchen cabinet industry where pieces are joined during installation processes. Those industries will use pigmented spray stains and pigmented wiping stains or glazes exclusively for that reason alone.
With most furniture finishes where dyes are used alone to achieve the total finish color, their intensity will fade more dramatically over a period of time than those that have a semi pigmented material applied over them. Color loss and fading will be less noticeable. These finishing systems are also much easier finishes to repair when damages occur or when defects become apparent. Touch up repairs blend in better. I enjoy the appearance and color stability of layered finishes. They are beautiful and well received in the field.
From contributor A:
To contributor C: Thanks for you lesson on colorants, but I do not agree with you on manufacturers using these colorants for preventing fading. There must be some, but as a rule, its not practice. The only time you hear about fading is after it happens - most finishers don't even think about that in their process. That’s why generally stain and clear coat finishes are in the majority. You can count the customers on your hands that ever mention fading when buying stains. Its only happens after they had a problem, or heard someone had a problem. There are many manufactures and woodworkers who only use clear coats. They don't think about fading, they think only about selling. This is just my point of view.
From the original questioner:
Many thanks for your comments. You've all helped me out on this. I've been a bit hesitant to try using more dyes for the fade reason. Is there a way to tell by the label if a dye is a micronized pigment or an older style aniline dye? We're going to be using MLC's Microton (which already sounds like a micronized pigment with the "micro").
From contributor B:
Generally Aniline dyes say "Aniline Dye" in the name or on the package. Lately I see Aniline dyes in Powder and not pre mixed into the solution; although I don't really look for them I'm sure that someone still makes them in solution.
From contributor A:
When you want to know, you have to ask. You are paying - know what you’re paying for. They do use different names, but they know what it is. If it’s Aniline, that’s not it!
From contributor A:
Purchase a small amount of material that you are interested in using. Finish a sample panel in the system you choose. Once thru dry, mask half the panel up completely, allowing no light to get to one half of the panel. Place it in the back dash of your car or someplace that allows full direct sunlight for a few weeks or a month or so. Unmask the panel and behold the results. Do your homework, test, and retest when in doubt. That way, what you tell your customers is sure to be "to the best of your knowledge."
