If lamp shines on sets for long time, will it cause yellowing

[ks6349]

It's just an example, I'd like to renovate my bedroom where it will display complete sets and I am thinking if I make lots of small lamp of white light like this on the shelf, shining on the sets for long time, the lamps will be switched off sometimes, will it cause yellowing or does only sunlight cause yellowing? The distance between the light source and the Lego sets will be even smaller than this example picture.

Edited October 13, 2021 by ks6349

[1980-Something-Space-Guy]

UV is what causes yellowing, and I've heard incandescent lamps do emit it. Apparently LEDs do not emit it, and it is what people use when they want to iluminate Lego sets without yellowing them, as far as I know.

Edited October 13, 2021 by BrickHat

[Peppermint_M]

UV light creates reactions with the plastic, so if you use LED you should be fine the whole time. Really, LED is a lot better because it illuminates the colours correctly and the variety of lights you can get will cover a room or fit under shelf units for display. 

I was thinking of getting a couple of those Ring Lights for my LEGO building space and for photography.  

[MAB]

And LED lights don't emit very much heat (via IR) at all. Whereas many incandescent bulbs emit most of the energy consumed that way rather than through light.

[MasterTyvokka]

Fluorescent bulbs are the worst UV emitters. I wouldn't use them in any collection room with stuff sensitive to UV. Both LED and incandescent emit some UV. But as MAB said LEDs don't have the heat of incandescents. 

Honestly I wouldn't worry about it with LEDs. Is there a window in the room? Is it permanently blacked out? What about humidity levels? Temp levels in the house?

The worst things for plastic are heat, humidity, and UV. I don't think the ABS Lego is made of has the same issues as the PVC used in some older action figures but those can become sticky in high humidity situations.

My point is plastic is going to degrade over time. Some quicker than others depending on composition, storage conditions, etc. I don't think some additional UV from an LED is going to make any difference under normal display circumstances unless you are going for storage in perfect conditions.

 

Edit: I believe halogens also emit significant UV and heat so I'd steer clear.

Edited October 14, 2021 by MasterTyvokka

[ks6349]

1 hour ago, MasterTyvokka said:

Fluorescent bulbs are the worst UV emitters. I wouldn't use them in any collection room with stuff sensitive to UV. Both LED and incandescent emit some UV. But as MAB said LEDs don't have the heat of incandescents. 

Honestly I wouldn't worry about it with LEDs. Is there a window in the room? Is it permanently blacked out? What about humidity levels? Temp levels in the house?

The worst things for plastic are heat, humidity, and UV. I don't think the ABS Lego is made of has the same issues as the PVC used in some older action figures but those can become sticky in high humidity situations.

My point is plastic is going to degrade over time. Some quicker than others depending on composition, storage conditions, etc. I don't think some additional UV from an LED is going to make any difference under normal display circumstances unless you are going for storage in perfect conditions.

 

Edit: I believe halogens also emit significant UV and heat so I'd steer clear.

Humidity?

I know that heat will affect plastic but it should only occur under experimental condition or at very high temperature that shouldn't happen in anywhere of the earth. But how humidity affects plastic? Plastic should be inert to water in the air

[MasterTyvokka]

http://www.mnhs.org/preserve/conservation/connectingmn/docs_pdfs/repurposedbook-plasticsandmodernmaterials_000.pdf

 

Keep in mind I'm not a chemist but come from years of collecting vintage action figures and spending time on related forums. The topic comes up frequently because white figures often turn yellow. Even though they were MIB and kept in dark conditions. Plastic offgases and one theory is that high humidity keeps the "gases" from escaping from the figures contributing to degradation. The same way sealing in a plastic bag would. Also just because something is impermeable to moisturize/ doesn't appear to be affected by it doesn't mean moisture can't do damage. I.e. rust. Like I said not a chemist but there could be some chemical reaction that occurs.

Define "very high temperature." Attics in my part of the U.S. can get to 120F+(50C+) during the summer and that can certainly degrade plastic (ask me how I know). I'm sure lesser temps could also degrade plastic. ( I only have anecdotal evidence that they can) Although, I think the better term would be accelerate degradation.

 

Edit: to get the link to work you may need to copy past it directly into your browser 

Edited October 14, 2021 by MasterTyvokka

[Mylenium]

15 minutes ago, MasterTyvokka said:

high humidity keeps the "gases" from escaping from the figures contributing to degradation.

Actually many plastics never polymerize 100 % and humidity provides a means of stabilizing the open ends of polymer chains by providing hydrogen. This would also prevent them from entering into other reactions e.g. with chlorine ions, which is what "gasing" most often comes down to - more reactive atoms and ions break free from their original compounds to form new connections and the leftovers migrate or evaporate from the material. Also of course oxygen reacts to ozone under UV light and in the process also absorbs those high energy photons. So there may be some wisdom in having a healthy humidity in your room, though the usual 35 to 55 percent in living homes should certainly suffice.

Mylenium

[MasterTyvokka]

7 minutes ago, Mylenium said:

Actually many plastics never polymerize 100 % and humidity provides a means of stabilizing the open ends of polymer chains by providing hydrogen. This would also prevent them from entering into other reactions e.g. with chlorine ions, which is what "gasing" most often comes down to - more reactive atoms and ions break free from their original compounds to form new connections and the leftovers migrate or evaporate from the material. Also of course oxygen reacts to ozone under UV light and in the process also absorbs those high energy photons. So there may be some wisdom in having a healthy humidity in your room, though the usual 35 to 55 percent in living homes should certainly suffice.

Mylenium

Sounds to me like a Goldilocks situation. You don't want overly dry but there appears to be evidence that high relative humidity can also cause issues. I guess the question is how much is necessary and how much is too much. I suspect your range is probably about right.

[1980-Something-Space-Guy]

37 minutes ago, MasterTyvokka said:

http://www.mnhs.org/preserve/conservation/connectingmn/docs_pdfs/repurposedbook-plasticsandmodernmaterials_000.pdf

 

Keep in mind I'm not a chemist but come from years of collecting vintage action figures and spending time on related forums. The topic comes up frequently because white figures often turn yellow. Even though they were MIB and kept in dark conditions. Plastic offgases and one theory is that high humidity keeps the "gases" from escaping from the figures contributing to degradation. The same way sealing in a plastic bag would. Also just because something is impermeable to moisturize/ doesn't appear to be affected by it doesn't mean moisture can't do damage. I.e. rust. Like I said not a chemist but there could be some chemical reaction that occurs.

Define "very high temperature." Attics in my part of the U.S. can get to 120F+(50C+) during the summer and that can certainly degrade plastic (ask me how I know). I'm sure lesser temps could also degrade plastic. ( I only have anecdotal evidence that they can) Although, I think the better term would be accelerate degradation.

 

Edit: to get the link to work you may need to copy past it directly into your browser 

Here I was thinking that storing minifigs in sealed bags was the way to go. What is one supposed to do, then? This link claims wrapping figures in tissue paper is better. That doesn't sound like a nice solution to me.

https://www.ala.org/alcts/preservationweek/advice/figurines

[MasterTyvokka]

8 minutes ago, BrickHat said:

Here I was thinking that storing minifigs in sealed bags was the way to go. What is one supposed to do, then? This link claims wrapping figures in tissue paper is better. That doesn't sound like a nice solution to me.

https://www.ala.org/alcts/preservationweek/advice/figurines

When I stored my action figures for a number of years between moving out of my parent's house and into my own I kept them in acid free archival plastic baggies ( cannot remember where I got them) and used a hole punch to punch holes in the bottom for air flow. The real valuable and old ones I wrapped in acid free tissue paper before putting them in the baggies. They came out in the same condition they went in but YMMV. Kept in cardboard shoe boxes (not tapes shut for airflow) in climate controlled closet.

FWIW it is worth most of this is conjecture on the action figure forums. While there is a lot of anecdotal evidence to back it up along with some science there have been no scientific studies to my knowledge. So nothing concrete to back up the potential (however unlikely) nonsense I'm spouting.

Edited October 14, 2021 by MasterTyvokka

[Peppermint_M]

ABS is pretty stable though. It is other stuff that can fail. Yellow Transparent stuff looks baaad after too much time. I was lucky with some purchases: The plastic bubble package was yellow but the clear plastic of the product was still fine.

[Faefrost]

Something to keep in mind. UV light doesn't cause yellowing. It simply accelerates it. The yellowing is caused by the Bromine Based fire retardents that were required to be added to plastics used in childrens toys and household electronics begining in the late 69's to early 70's (depending on region). The Yellowing is going to happen eventually. Even if the plastic toy is vacuum sealed an entombed in climate controlled darkness. 

But like I said without the uv light boost it can take decades sometimes. How much and how fast a part yellows will be unpredictable. The fire retardent was added at the point the plastic pellets are melted. Basically just dump a bucket in. So amounts of the FR will vary from batch to batch, and the type and formulation changed over time. Modern FR's dont yellow anywhere near as bad as the ones used in the 70's. 

To slow yellowing avoid direct sunlight on the toys. Unless you are using flourescent grow lights or aquarium lighting in your display normal household lighting should be a non issue. LED lighting is probably the best option as it has no UV and very little heat output. 

[TeriXeri]

30 minutes ago, Faefrost said:

Something to keep in mind. UV light doesn't cause yellowing. It simply accelerates it. The yellowing is caused by the Bromine Based fire retardents that were required to be added to plastics used in childrens toys and household electronics begining in the late 69's to early 70's (depending on region). The Yellowing is going to happen eventually.

Can confirm, I've seen heavy yellowing on an old crater space baseplate while it was in dark storage for like 15 years, but that part was probably 40 years old since produced as it was from a 1979 set.

Baseplate aren't typical "bricks" though.

Edited October 14, 2021 by TeriXeri

[Faefrost]

23 minutes ago, TeriXeri said:

Can confirm, I've seen heavy yellowing on an old crater space baseplate while it was in dark storage for like 15 years, but that part was probably 40 years old since produced as it was from a 1979 set.

Baseplate aren't typical "bricks" though.

It doesn't really matter if it's a typical brick. In this case the baseplates are polystyrene vs the bricks ABS. What yellows is the flame retardent additive that is put in both. Which decays over time. Limiting oxygen exposure might slow it as its an organic reaction? But not much else. 

[1980-Something-Space-Guy]

41 minutes ago, Faefrost said:

It doesn't really matter if it's a typical brick. In this case the baseplates are polystyrene vs the bricks ABS. What yellows is the flame retardent additive that is put in both. Which decays over time. Limiting oxygen exposure might slow it as its an organic reaction? But not much else. 

Limiting oxygen exposure might suggest that keeping them sealed is better, no?

[Toastie]

All good suggestions here and very good analyses, as far as I am concerned!!!

Where are you heading to, though? Colors forever, internal ABS structure forever? What is "ever"? Your lifetime, or some stretch of "your" time on Earth? To do what (then)? Resale or re-enjoy?

When a brick of whatever color (some are more demanding, others are boldly keeping up with "demand") is changing characteristics, this is usually called "life" maybe even "evolution" (can't keep your color? Sorry you are out; other species are coming ).

Now, with regard to the OP: No light, no oxygen, and temperatures well below 0 degrees Celsius is the way to go. Not too low, as this is also detrimental to - well - plastic.

More on topic: Low temperature, only visible light exposure (e.g. from LED's, good choice) will probably make the bricks live longer than you can (currently) hope for. Let's not elaborate on Oxygen.

Suggestion: Play well. It renders the mummification issues far less stressful. And I believe a little or even more "weathering" is going very well with the idea of LEGO.

Just my two cents, absolutely nothing "serious".

All the best,
Thorsten

 

[MasterTyvokka]

4 hours ago, Peppermint_M said:

ABS is pretty stable though. It is other stuff that can fail. Yellow Transparent stuff looks baaad after too much time. I was lucky with some purchases: The plastic bubble package was yellow but the clear plastic of the product was still fine.

True. Typically with the action figures the legs and arms which are slightly flexible and made of some form of PVC are yellow whereas the torsos made of ABS are not found yellowed as often.

3 hours ago, Faefrost said:

Something to keep in mind. UV light doesn't cause yellowing. It simply accelerates it. The yellowing is caused by the Bromine Based fire retardents that were required to be added to plastics used in childrens toys and household electronics begining in the late 69's to early 70's (depending on region). The Yellowing is going to happen eventually. Even if the plastic toy is vacuum sealed an entombed in climate controlled darkness. 

But like I said without the uv light boost it can take decades sometimes. How much and how fast a part yellows will be unpredictable. The fire retardent was added at the point the plastic pellets are melted. Basically just dump a bucket in. So amounts of the FR will vary from batch to batch, and the type and formulation changed over time. Modern FR's dont yellow anywhere near as bad as the ones used in the 70's. 

To slow yellowing avoid direct sunlight on the toys. Unless you are using flourescent grow lights or aquarium lighting in your display normal household lighting should be a non issue. LED lighting is probably the best option as it has no UV and very little heat output. 

I think the real trick, since degradation cannot be stopped but only slowed is to balance prevention with ability to display, enjoyment, etc. 

 

You might be right about normal household lighting but I think could also depend on how close it is. Personally I wouldn't risk using florescent or halogen bulbs as display lighting.

2 hours ago, BrickHat said:

Limiting oxygen exposure might suggest that keeping them sealed is better, no?

Maybe but that is only one particular type of degradation. It's possible you end up trading one for another. Which is worse? IDK.

Edited October 15, 2021 by MasterTyvokka

[Faefrost]

4 hours ago, BrickHat said:

Limiting oxygen exposure might suggest that keeping them sealed is better, no?

The packaging isn't vacuum sealed. There's air and oxygen in it. 

3 hours ago, Toastie said:

All good suggestions here and very good analyses, as far as I am concerned!!!

Where are you heading to, though? Colors forever, internal ABS structure forever? What is "ever"? Your lifetime, or some stretch of "your" time on Earth? To do what (then)? Resale or re-enjoy?

When a brick of whatever color (some are more demanding, others are boldly keeping up with "demand") is changing characteristics, this is usually called "life" maybe even "evolution" (can't keep your color? Sorry you are out; other species are coming ).

Now, with regard to the OP: No light, no oxygen, and temperatures well below 0 degrees Celsius is the way to go. Not too low, as this is also detrimental to - well - plastic.

More on topic: Low temperature, only visible light exposure (e.g. from LED's, good choice) will probably make the bricks live longer than you can (currently) hope for. Let's not elaborate on Oxygen.

Suggestion: Play well. It renders the mummification issues far less stressful. And I believe a little or even more "weathering" is going very well with the idea of LEGO.

Just my two cents, absolutely nothing "serious".

All the best,
Thorsten

 

Which brings another fun point that people never realize. Color = Chemistry. The process of making the plastic a certain color changes the plastics characteristics based on the properties of the substances used to pigment the plastic. 

Blue and black are two of the oldest and most stable pigments for plastic. They are readily available, mix well, are cheap to acquire and can be injection molded at a wide range of temperatures and pressures. 

At the opposite end of the spectrum is pink. The compounds to generate pink plastic are only found in a few places, require more handling and processing, resulting in much more expensive color additives. And the color does not mix well with the plastic requiring much higher temperatures and pressure to get good results. 

If you've ever heard of the "pink tax" in the news media, see the above to understand what is really going on there. A pink shaving razor is sold for 10-20% more than a black or blue one because the pink color costs more to produce. It probably also explains why Friends sets feel a bit more overpriced than some other lines. The parts color price is baked into Lego's design point system. 

And we all know the problems of brittle parts in Redish Brown and Dark Red parts. The issue there is the chemistry related to those colors. 

[MAB]

10 hours ago, Faefrost said:

If you've ever heard of the "pink tax" in the news media, see the above to understand what is really going on there. A pink shaving razor is sold for 10-20% more than a black or blue one because the pink color costs more to produce. It probably also explains why Friends sets feel a bit more overpriced than some other lines. The parts color price is baked into Lego's design point system. 

Pink tax isn't anything to do with the colour, aside from linking the colour pink to female. The pink tax is gender based pricing, the pricing of items for women higher than items for men or more general items used by both genders.