Does a doll ever stop yellowing? Is there a “max?”

I don't have any direct experience with resin, but I am speaking from a chemical standpoint here, please take what I say with a grain of salt because I am not experienced with resin. So the "yellowing' is actually a breakdown of the red dye within a doll. Red Dyes are more susceptible to light and thus degrade over time. At an eventual point in time the red dye would break down completely and thus the doll should cease to yellow...because there is no red to degrade without sanding deeper into the resin to expose the parts where the red molecules are too deep for the sun to penetrate. Do I know how yellow that would be? No, I have no idea. Also, white dolls still tend to yellow over time so it is possible that the other pigments break down and the doll would still change color even after all of the red has faded. Eventually, there would have to be a point where the doll would stop yellowing unless exposed to drastic measures that affect the chemical composition (like leaving it in a car in direct sunlight so heat and sunlight are constant).

 

I have no idea, but that’s something I’d be curious to learn about too! I imagine they’d probably reach a max yellow, but still become kind of dingy and dirty over time from air pollutants/dirt/skin oils. I googled antique resin goods, and it looks like they turn a banana-yellow color (sometimes with greenish undertones), but many have a kind of dirtiness in the crevices. It looks like it’s from not being stored/handled properly over the decades. So I think making sure to handle dolls with clean hands and keeping them in a clean place is key to keeping them looking nice!

 

I have some pretty old dolls and I feel like the most dramatic change in color happens in the first 5 years. Most of my dolls are now 8+ years old and there are very few that are really yellowed, none are greened (this problem was mostly isolated to older dolls from certain makers in certain colors) and the most yellow one I have was used when I got him in 2012 and he doesn't look any more yellow now. I hope that's helpful!

 

My understanding is, what you're describing is what we come to call "greening". The yellowing process, while it can happen in this way, is often by oxidation of the plastics. You can see prime examples of this with the grey/white computer chases from the 80s and 90s that have turned a deep yellow over the years. To that point, I would say plastic does have a maximum in the oxidation version of yellowing, as well, and it can be remedied to some extent (sanding, oxi-clean baths...) but it will come back, sometimes worse.

 

Does anyone have photos of what beauty green looks like? Google is as unhelpful as ever when I try to find references for it.

 

Oh that's actually really helpful! And honestly not nearly as bad as I've worried about, though I'm a bit worried about blue skin

 

Just to briefly chime in, with Urethane/Polyurethane type of resin, the yellowing process is caused by the plastic molecule adding on an oxygen atom into its molecular structure. So yes, theoretically, it should stabilize once all of the free ions are bonded. Just be careful about exposing the doll to things like acid rain or other mild acids, since Urethane type plastics can be vulnerable to them (which is why they aren't used in medical devices). Basically, limit their time outside and wash your hands before directly handling the plastic.

 

From what I've heard, blue tends to mellow into gray hues.

 

The most dramatic yellowing I've seen came from The Boob Experiment (I apologize for forgetting the thread's actual title.) Two people removed the breasts from their dolls as part of their modding process. The breasts were then placed in different locations over a period of time to see how they yellowed. Most were different shades of very light to light yellow. The breasts placed on the lawn for six months were the color of banana peels.

 

I have 2 dolls manufactured in 2005 - French resin Narae and Elfdoll Soah. Both have yellowed but not severely or what I would call green but now I’ll take a close look and pics that I’ll post here in the morning.

 

That is actually really perfect! Since he's supposed to be a very desaturated grey-blue (though I often draw him more saturated because the way I layer and also it's fun)
I'm so relieved to hear it!

Thank you!

 

I understand the mechanism why they yellow but I always wondered if there was a limit as well. I had a Volks doll made in 2005 and when I sold him early this year he was super yellowed. I still think it didn’t look ugly though. For sure not a banana.
I can also say it got that bad because it was my first bjd and I didn’t know anything about them. He was there sitting in the sun close to my window and all for at last 3 or 4 years.
I’ve bem to mandarake shops several times and they have done pretty old and pretty yellowed dolls there. Still, most are “ok” to me.
I wonder what happens to pink resin. Maybe they just loose all the red and become yellow dolls one day.

 

It would be funny to order a doll in a skintone for planned yellowing.

 

I don't have any accurate pictures on hand unfortunately, but I do believe I have one doll who has reached max capacity on yellowing. (I hope?) I'm at least the third owner of my Unoa, and the previous one had him since 2008. I'm not entirely sure when he was made but the sculpt was released in 2005, so he's potentially sixteen years old now.

He hasn't gotten any more yellow in the six years I've owned him, but I would still describe him as being... A subtle banana. Still noticeably discoloured, especially in comparison to newer dolls, but closer to the colour of the banana itself as opposed to it's peel. Maybe if I left him in direct sunlight for months his resin would change more, but I think he's as discoloured as he's going to get based on age alone.

 

I’m having trouble getting the images to post in this reply.

I’m the 3rd owner of both these dolls. Here are the photos of my Elfdoll Soah and French Resin Narae. Both were made in 2005. I purchased them in 2009. Both have yellowed, but I would not call either banana yellow.
PXL_20210601_015004406
The Soah has yellowed evenly. The best evidence is comparing the inside of her head to the outside.

PXL_20210601_014704472.MP
My Narae, on the other hand, came to me with 'tan lines' - a previous owner had kept the gal in a summery outfit and took her outdoors. I managed to minimize the yellowing with several oxyclean washings and sanding. I believe her original color was Pinky French Resin. She is definitely more yellow than when she arrived over a decade ago.

 

Thanks for the explanation! I always wondered about the science behind it, and that was fascinating to read.