"How lightfast are modern acrylics" Topic

I had an interesting discussion with a friend yesterday about how lightfast model or artists paints are.

My position is this:
Providing you use an all acrylic process from undercoat to varnish and the pigments you use are designed as lightfast, as the best quality materials are, and providing the figures are not in sunlight the colours should remain true. For example, the whites remain white without shifting to a yellow or blue tint.

I have figures painted 14 years ago with Vallejo, that have been stored in boxes, and that remain the same colour as those painted in the last few months. ie. the colours have remained lightfast.

My friend contests this view saying that all colours must change over time. I concede this is true and quite likely to happen if any oil / enamel based paints are used. I have witnessed this with my own collection where I used enamels.

What to do you think?

i think you are more right than your freind, older pigments tended to be organics for certain colours, and would fade due to oxidation or light ( anything with the word Lake in the title is an organic pigment, and fades, hence the poblem for rail modelers with shades such as crimson lake) Ive a freind who has done quality control in a paint factory, and know more abought it than most sane folks want to know.

I only use craft paints, and over the past 15 years, I have not noticed fading, or changes yet. My figures are mostly stored out of sunlight, and I do not have florescent lights to bleach their colors, either.

Florescent lights are the biggest color killers. With everyone "going green", this will become an issue, not only with miniatures, but also everything else: furniture, paintings, photographs, posters, anything with pigment in it. Florescent lights pump out Ultra-Violet light, which kills pigments, organic, or otherwise, over time.

To maintain colors on your miniatures, be sure to store them in light-proof cupboards, boxes, whatever, especially if you have florescent lights in your game room (CFL's are "compact florescent lights"…). Florescent lights pump out the Lumens, per watt, like nothing else, so they are incredibly efficient, and easy on the electric bill, but they have their drawbacks. Cheers!

I doubt very much that any organic pigments have ever been used in model paints. Even in artists ranges they have been rare and usually included only for specialist use (such as for restoration) or where a particular technique uses that colour as a 'standard' (such as the fugitive reds popular with flower painters).

Lake pigments are not necessarily organic (in fact very few are nowadays) but they are often fugitive because of the nature of the dyes used (a lake is a dye precipitated on a substrate or inert salt) and not because they are organic.

Storing your painted minis in a box does not test if the paint is lightfast.

Some manufacturers do provide information about how lightfast their paints are. Those reports indicate that it varies by pigment type. There is an ASTM standard for measuring lightfastness of pigments.

I suspect it may be a good idea to keep them in a darkened place, if you value them, or at least in a UV film-treated display case, if not.

Thanks for your responses.

@timlillig

I agree with you but I'm edging my bets as I value them. I had to repaint the whites on 400 figures that were stored in boxes in a cupboard but the whites still took on a yellow tint. They had been painted and varnished using enamel. Since repainting them about 12 years ago in acrylic they haven't shifted. Not a scientific test at all but one that is good enough to convince me to stick to high quality acrylics.

I note that some inkjet materials are guaranteed lightfast for something like 200 years. I guess they have tested this by exposing them to very high levels of fluorescent light but I'd like to know how they can give their papers and inks that degree of longevity.

I also note that archival quality museum storage boxes are acid free not sure what that means to us storing figures though.

I suspect it is the varnish that has yellowed your white paint.

Same thing happened to mine, over time, even though kept out of the light.

The infamous, "lead rot", has been attributed to acid reacting with the lead used in figures made out of lead compounds, back in the 80's, and before. The acid issue, with regards to museum storage boxes, pertains to paper reacting with acid: it turns the paper yellow, brittle, and it begins to crumble (newspaper print is paper containing acid, and it decays over time, as described).

With regards to your figures' white parts yellowing, over time, this may have happened due to the enamel paint pigments. I've not heard of modern acrylic paints suffering this problem. As I said, I use craft acrylic paints, only, typically less than $1.50 USD per 2 oz. bottle; many of my figures were painted 15+ years ago, and they show no yellowing, or fading that I can see. The higher quality acrylics, have better pigment size of bits in their suspension, as well as having a higher density of pigment within their suspension (require fewer coats to cover) -- those are the major differences, not so much the lightfastness, as far as I know.

As was stated, artists' paints will have their lightfastness quality available. For craft paints, since they are not considered artist quality, no one cares, so the information is not readily available. However, they do make craft paints for use outdoors -- these will be more resistant to UV, so they should offer better lightfastness.

If you cannot locate the lightfastness of a given paint, try contacting the manufacturer, and ask them about it. I am certain they know, and they will very likely be willing to share it with you, as well. Cheers!

There are some UV protective matte varnishes out there. Krylon's Gallery Series is one. They are a little pricier for obvious reasons but they aren't much more than regular spray varnishes. They are designed for museum and gallery use.