Yellowing - How To Prevent?

[vladykins]

Fun yellowing thing: My original Yamato v1 Hikaru VF-1A has been with me since it was released...damn, was it really that long ago? I've had it sitting in GBP armor since the armor was released for the v1s, so almost as long. I've been considering ditching the armor so I pulled it down to see the state of the yellowing after all that time. Transformed it back into fighter mode which is where it will likely stay from now on.

 

Has it yellowed? Oh yes, it has yellowed a lot, unevenly as is wont to do with this set of toys. The odd thing for me: the shoulders and the heat shield have actually turned gray?

 

 

 

[MacrossJunkie]

Wow, that is pretty insane.  Never seen white turn to grey before.  That looks like cases of plastic just breaking down over time rather than exposure to sunlight, particularly since areas like the chest piece would have been covered by the GBP armor.

As expected, painted parts like the white on the transparent wing lights and the die cast legs are still pristine white. They must have had some very different mixtures in the plastic batches for one wing to turn sherbet orange while the other one is relatively okay.

[Sanity is Optional]

Also how one of the gear-doors on one side is safe, but all the other gear doors are yellow. Very interesting.

[vladykins]

What's really weird is I thought the heat shield was red originally but the shoulders definitely weren't red, so for both of them to end up gray is just really bizarre. Going to have to look through old pictures to confirm. I've had the GBP on there so long I forget what it all looked like originally.

[Slave IV]

Another example of way too many factors at play...Who knows? Maybe the sweat of a worker got mixed in with only the plastic that went into that lower left gear door and changed the properties of how the color changed? Not worth the time to figure out to me but again, I'd love to see someone come up with a definitive answer to all this.

[MacrossJunkie]

7 minutes ago, vladykins said:

What's really weird is I thought the heat shield was red originally but the shoulders definitely weren't red, so for both of them to end up gray is just really bizarre. Going to have to look through old pictures to confirm. I've had the GBP on there so long I forget what it all looked like originally.

The heat shield was red, yes, but I think it's still stored away somewhere else. That looks like a replacement piece put in to attach a GBP armor piece as it has a square hole for a peg or something. 

For comparison reference:

http://www.macrossworld.com/macross/toys/yamato_vf1/battroid/_yamato_vf1_battroid.htm

[vladykins]

3 minutes ago, MacrossJunkie said:

The heat shield was red, yes, but I think it's still stored away somewhere else. That looks like a replacement piece put in to attach a GBP armor piece as it has a square hole for a peg or something. 

For comparison reference:

http://www.macrossworld.com/macross/toys/yamato_vf1/battroid/_yamato_vf1_battroid.htm

Aha- that solved the mystery. As I said, I'd had it on there for so long I'd forgotten most of it (looking up, it looks like about 16 years now since the GBP was released). The gry shoulders were actually add-ons to fit the GBP on there, along with the gray heatshield replacement to hold on the front. At least the materials didn't gray weird! 

[Lolicon]

Holy hell that is insane!

If you can get the rest of it yellowed like the one wing, you'll be well on your way to making your own custom VF-1D. 

[tekering]

9 hours ago, Lolicon said:

Holy hell that is insane!

It's worse than any Takatoku I've ever seen.  

How many years of sunbathing did it take to achieve those results, @vladykins?

[BlueMax]

1 hour ago, tekering said:

It's worse than any Takatoku I've ever seen.  

How many years of sunbathing did it take to achieve those results, @vladykins?

i'm willing to bet minimal sunlight...at most just exposure to ambient and maybe flourescent light. Also, probably displayed in-situ for close to 15 years?

[vladykins]

2 hours ago, tekering said:

It's worse than any Takatoku I've ever seen.  

How many years of sunbathing did it take to achieve those results, @vladykins?

It's been sitting on various shelves in my office with GBP on for about 16 years (and I only know that from Jenius' site telling me it was released in 2014). It's been moved from shelf to shelf but was mostly out of the way and out of direct sunlight (usually on higher up shelves).

What's funny is I saw someone else's version they are selling and, like mine, they have one wing waaaaay yellower than the other.
 

 

11 hours ago, Lolicon said:

Holy hell that is insane!

If you can get the rest of it yellowed like the one wing, you'll be well on your way to making your own custom VF-1D. 

 

 

If I didn't already have the Yamato 1/60 v1 and v2...

 

I am considering custom painting it if my painting skills don't totally suck. These Hikaru 1As go for next to nothing so I won't be destroying much value, even with my terrible painting skills.

 

1 hour ago, BlueMax said:

i'm willing to bet minimal sunlight...at most just exposure to ambient and maybe flourescent light. Also, probably displayed in-situ for close to 15 years?

Yep- pretty much. Used to be way top of a book shelf for most of that time, then got moved maybe two years ago to a shelf we built over the closet in my "office". I may have had CFLs in there for a time but rarely used them.

 

 

 

[MacrossJunkie]

Yeah, that's just really crappy plastic you're dealing with there.  There's just no way some of those landing bay doors could turn THAT orange from UV alone, much less when they've been covered the whole time by the GBP armor. The fact that the plastics changed color at different rates, even when covered, shows that the plastic itself (and how much the chemical components that make it up breaking down or catalyzing) can be a high contributing factor to yellowing itself. 

Though I am willing to bet that if you had stored it in the freezer, that sort of temperature might have slowed the yellowing 

Edited September 11, 2020 by MacrossJunkie

[vladykins]

Given it is pretty much worthless, maybe I should just try and make it an Alaska Base custom now?

[Anasazi37]

2 hours ago, MacrossJunkie said:

Yeah, that's just really crappy plastic you're dealing with there.  There's just no way some of those landing bay doors could turn THAT orange from UV alone, much less when they've been covered the whole time by the GBP armor. The fact that the plastics changed color at different rates, even when covered, shows that the plastic itself (and how much the chemical components that make it up breaking down or catalyzing) can be a high contributing factor to yellowing itself. 

Though I am willing to bet that if you had stored it in the freezer, that sort of temperature might have slowed the yellowing 

The yellowing on the landing gear doors (and the missiles) is a known issue on the v1 TRU-exclusive VF-1A CF. I didn't know about the issue until I pulled mine out of its box for the first time earlier this year. I bought it in early 2002 and it was in dark, temperature-controlled storage the entire time. Only the doors and the missiles were yellow--that exact sickly shade of yellow--and there was an awful smell. I think the plastic outgassed over the years and changed color during the process. UV might accelerate that process. I ended up re-boxing my TRU and picking up the non-exclusive CF that was released a few months later. Everything is bright white on that one.

[Mog]

So basically we should store our toys in a lead-shielded container that actively sucks out all oxygen and other gases within the container, allows 0.000000000001 percent outside ambient light to seep into the container, while maintaining a constant 20 degrees Celsius temperature, preferably in a location that minimizes the impact of the outside atmosphere, air pressure, background radiation, and gravity.

[vladykins]

19 minutes ago, Anasazi37 said:

The yellowing on the landing gear doors (and the missiles) is a known issue on the v1 TRU-exclusive VF-1A CF. I didn't know about the issue until I pulled mine out of its box for the first time earlier this year. I bought it in early 2002 and it was in dark, temperature-controlled storage the entire time. Only the doors and the missiles were yellow--that exact sickly shade of yellow--and there was an awful smell. I think the plastic outgassed over the years and changed color during the process. UV might accelerate that process. I ended up re-boxing my TRU and picking up the non-exclusive CF that was released a few months later. Everything is bright white on that one.

It looks like the upper arms and hands were made of a different plastic like PVC, because mine is sticky like the plasticizer came out, so I'm wondering if that is some of the problem. Some of my gashapon gundams had the same issue and I had to clean those all up with some goo b gone and soap.

[Anasazi37]

3 hours ago, Mog said:

So basically we should store our toys in a lead-shielded container that actively sucks out all oxygen and other gases within the container, allows 0.000000000001 percent outside ambient light to seep into the container, while maintaining a constant 20 degrees Celsius temperature, preferably in a location that minimizes the impact of the outside atmosphere, air pressure, background radiation, and gravity.

You forgot to add "launch container into space"

[MacrossJunkie]

3 hours ago, Mog said:

So basically we should store our toys in a lead-shielded container that actively sucks out all oxygen and other gases within the container, allows 0.000000000001 percent outside ambient light to seep into the container, while maintaining a constant 20 degrees Celsius temperature, preferably in a location that minimizes the impact of the outside atmosphere, air pressure, background radiation, and gravity.

And as close to 0 kelvin as possible. It can't deteriorate if the molecules can't move.

[Mog]

3 hours ago, Anasazi37 said:

You forgot to add "launch container into space"

Well, launching it into space may reduce the impact of gravity, but we would be increasing the outside temperature variations on the hypothetical container.

Plus, there's all that radiation we have to deal with if we launch it too far out of Earth's magnetic bubble.

2 hours ago, MacrossJunkie said:

And as close to 0 kelvin as possible. It can't deteriorate if the molecules can't move.

That's assuming the plastic (and other toy materials) can survive the temperature drop to absolute zero. 

That's why I said to keep the inside of the container at a constant 20 degrees Celsius (basically cool room temperature).

 

So, should we go with a full hazmat suit before we put the toys in the container (to prevent any outside contaminants from interacting with the toys)?  Or will wearing museum curator level gloves and holding our breath be sufficient to minimize the impact of any contaminants and that pesky oxygen?

[sqidd]

13 minutes ago, Mog said:

 

 

So, should we go with a full hazmat suit before we put the toys in the container (to prevent any outside contaminants from interacting with the toys)?  Or will wearing museum curator level gloves and holding our breath be sufficient to minimize the impact of any contaminants and that pesky oxygen?

[Mog]

So, hold my breath,

put on museum curator level gloves (to prevent getting oils/sweat on outside of hazmat suit),

continue holding breath,

put on hazmat suit,

continue holding breath,

put toy in hypothetical container,

try to focus despite lack of oxygen in brain,

close container, and

pray that my medulla oblongata reminds my lungs to start breathing again.

Edited September 12, 2020 by Mog

[DewPoint]

One day we'll all find out that it is the plastic interacting with neutrinos and there us absolutely nothing we can do about it.  That or it proves the existence of dark matter. 

[Bobby]

Farmer: This is so painful it's like watchin' paint dry!

Worker: You mean like so slow it's like watchin' grass grow!

Macross Fan: Yeah totally, it's like watching my valkyrie yellow! 

Farmer: What in tarnation is he talkin' about?

 

[sqidd]

Hey kids. Can you check my math here? I’m sort of sleep and feeling really dumb. Here is what I got on line to figure out the bottom line:

 

To do your conversion, remember that 1 foot-candle is about 10 Lux

(closer to 10.76). The term "Lux" means "lumens-per-square-meter".

Using a visible light meter, get a light reading in (or convert to)

Lux. There are 1,000 square centimeters in a square meter, so divide

the Lux number by 1,000. You will likely get a decimal number that

represents the "lumens-per-square-cm". Measuring your UV content

with your UVP/UVX Radiometer will give you a UV value in

"microwatts-per-square-cm". Compare the "lumens-per-sq-cm" to the

"microwatts-per-sq-cm" and cancel out the dimensional term. You will

then know the value in microwatts-per-lumen. The "safe range" you

mention (10 to 75 microwatts per lumen) would vary depending on the

level of illumination. If you were looking at a work on paper that

were illuminated at 50 lux, then the "safe range" you are seeking

would be 0.5 to 3.75 microwatts of UV per sq cm. At 100 lux, the

range would be 1.0 and 7.5, etc.

 

-The visible light meter reads 4600 lux

 

-The UV meter reads 12 µW/cm2

 

-Divide lux by 1000 = 4.6 lux/cm2

 

-Cancel out the dimension - 12 µW/4.6 lux.

 

-Bottom line = 2.608 µW/lumen?

 

Safe range is 10-75 microwatts per lumen. I have no idea what it’s not 0-75 microwatts per lumen . Does 1-9 microwatts per lumen create some sort of inter-dimensional rift where light works differently because…….reasons?

[Anasazi37]

4 hours ago, sqidd said:

Hey kids. Can you check my math here? I’m sort of sleep and feeling really dumb. Here is what I got on line to figure out the bottom line:

 

To do your conversion, remember that 1 foot-candle is about 10 Lux

(closer to 10.76). The term "Lux" means "lumens-per-square-meter".

Using a visible light meter, get a light reading in (or convert to)

Lux. There are 1,000 square centimeters in a square meter, so divide

the Lux number by 1,000. You will likely get a decimal number that

represents the "lumens-per-square-cm". Measuring your UV content

with your UVP/UVX Radiometer will give you a UV value in

"microwatts-per-square-cm". Compare the "lumens-per-sq-cm" to the

"microwatts-per-sq-cm" and cancel out the dimensional term. You will

then know the value in microwatts-per-lumen. The "safe range" you

mention (10 to 75 microwatts per lumen) would vary depending on the

level of illumination. If you were looking at a work on paper that

were illuminated at 50 lux, then the "safe range" you are seeking

would be 0.5 to 3.75 microwatts of UV per sq cm. At 100 lux, the

range would be 1.0 and 7.5, etc.

 

-The visible light meter reads 4600 lux

 

-The UV meter reads 12 µW/cm2

 

-Divide lux by 1000 = 4.6 lux/cm2

 

-Cancel out the dimension - 12 µW/4.6 lux.

 

-Bottom line = 2.608 µW/lumen?

 

Safe range is 10-75 microwatts per lumen. I have no idea what it’s not 0-75 microwatts per lumen . Does 1-9 microwatts per lumen create some sort of inter-dimensional rift where light works differently because…….reasons?

Keep in mind that lumen, as a unit of measurement, is for the visible portion of the spectrum (roughly 400-700 nanometers). UV is outside of that range (100-400 nanometers). In other words, the radiometer is measuring transmitted light in one part of the spectrum and you have a manufacturer's estimate for light transmitted by a bulb in another part. The values don't overlap, so you can't combine them in this way. Not that I ever thought I'd be posting a picture of the electromagnetic spectrum in this forum, but the following shows you why it won't work (UV is to the left of Visible)

This is a crude analogy, but it's like you have an estimate of engine performance in one set of units that is specific to driving between 40 and 70 mph, but what you really want is an estimate for between 10 and 40 mph in another set of units, so you're doing the unit conversion and trying to use the estimate you have, but the engine is highly likely to perform differently in the other range and, more importantly, you have no actual data in that range.  To do the math you want to do, you'd need a lumen number specific to UV...which doesn't exist...because lumen is for the visible portion of the spectrum...so you really need a UV radiometer. On top of everything else, lumen isn't an absolute measurement, like the radiance measured by a radiometer. How the human eye sees that light is accounted for in the value using a subjective model (luminosity function), so scientists don't like it, but it seems to make sense to consumers. The wavelength limitation and subjectivity of lumen is mentioned in the first few sentences of its Wikipedia article, although if you're not familiar with radiometry, it's super-easy to miss the significance:

https://en.wikipedia.org/wiki/Lumen_(unit)

Edited September 13, 2020 by Anasazi37

[sqidd]

1 hour ago, Anasazi37 said:

Keep in mind that lumen, as a unit of measurement, is for the visible portion of the spectrum (roughly 400-700 nanometers). UV is outside of that range (100-400 nanometers). In other words, the radiometer is measuring transmitted light in one part of the spectrum and you have a manufacturer's estimate for light transmitted by a bulb in another part. The values don't overlap, so you can't combine them in this way. Not that I ever thought I'd be posting a picture of the electromagnetic spectrum in this forum, but the following shows you why it won't work (UV is to the left of Visible)

This is a crude analogy, but it's like you have an estimate of engine performance in one set of units that is specific to driving between 40 and 70 mph, but what you really want is an estimate for between 10 and 40 mph in another set of units, so you're doing the unit conversion and trying to use the estimate you have, but the engine is highly likely to perform differently in the other range and, more importantly, you have no actual data in that range.  To do the math you want to do, you'd need a lumen number specific to UV...which doesn't exist...because lumen is for the visible portion of the spectrum...so you really need a UV radiometer. On top of everything else, lumen isn't an absolute measurement, like the radiance measured by a radiometer. How the human eye sees that light is accounted for in the value using a subjective model (luminosity function), so scientists don't like it, but it seems to make sense to consumers. The wavelength limitation and subjectivity of lumen is mentioned in the first few sentences of its Wikipedia article, although if you're not familiar with radiometry, it's super-easy to miss the significance:

https://en.wikipedia.org/wiki/Lumen_(unit)

I never miss an opportunity to use this.

I get where you're coming from above. And that blurb I found above is bull.

Am I correct in assuming that there is no practical way for me to measure the UV that the bulbs in my cab are putting out? I'm not a fan of "just trust it", but that sounds like what I'm going to have to do.

 

Edited September 13, 2020 by sqidd

[Lolicon]

Encase your valks in amber so future humans will have a pristine molecular sample they can program into their replicators and create as many valks as people want. 

Although some people will probably say that replicated valks don't feel as good in the hand as original factory-built valks...

[Anasazi37]

14 hours ago, sqidd said:

I never miss an opportunity to use this.

I get where you're coming from above. And that blurb I found above is bull.

Am I correct in assuming that there is no practical way for me to measure the UV that the bulbs in my cab are putting out? I'm not a fan of "just trust it", but that sounds like what I'm going to have to do.

 

Okay, that's both disturbing and funny. Based on your previous post, it sounds like you have a UV radiometer/light meter with the following specs:

• The display is in µW/cm2 (microwatts per square centimeter)
• UV AB Measurement Range: 0 to 2999 µW/cm2; It only measures UV AB light power output, but not the wavelength.
• Spectral Detection Range: 240 to 370 nm; Peak point: 352 nm. It does not measure UVC.
• Measurement accuracy: ±4% ±1 digits; Resolution:1.0 µW/cm2

Unless a bulb manufacturer gives you information about the amount of UV light the bulb is sending out, you'll have to make a direct measurement. The specs for the meter claim that it's accurate to within 4%, so you could take the reading you get and create a range for your bulb, with your reading minus 4% on the low end and your reading plus 4% on the high end. And you're getting a more general estimate for all of UVA/B, what is sometimes called an integrated value or a band pass value. The sensor gathers in light across a broader range of wavelengths and then averages all of that to produce a single value, so any specific behavior of UV light at specific wavelengths is lost. That's why lab-grade spectrometers cost so much. Not only are they calibrated, but they also make multiple measurements over smaller chunks of the range, sometimes hundreds or thousands of them, which can then be used to create a continuous line that looks something like this, which I randomly grabbed from the results of a Google Image Search:

So, back to your question about how much UV light is too much and can you convert the output from your UV meter into something useful. I would argue that µW/cm2 is a useful measurement because it's absolute and describes how much energy is hitting a surface, which is exactly what you want to know. The technical term for it is irradiance:

https://en.wikipedia.org/wiki/Irradiance

Irradiance is widely used in the scientific and engineering communities, so you're on solid ground there. So, I think it's more about taking values used by communities who worry about UV light damaging stuff and converting them to irradiance, but let's put a pin and that in see what they actually do. It does seem like the cultural heritage preservation crowd, i.e., museums, has thought about this quite a bit. I found what looks to be a pretty useful resource from the Canadian Conservation Institute (likely far more credible than a random reply on a message board):

https://www.canada.ca/content/dam/cci-icc/documents/services/conservation-preservation-publications/canadian-conservation-institute-notes/2-2-eng.pdf

It opens by saying that no one outside of the museum world thinks about UV in relative terms, which is what that µW/lumen measurement is: a ratio between light you can't see and light you can. Hence my previous comment about how you can't take a visible spectrum, lumens-only measurement and convert it to one that is relevant for UV, however if you have instruments that can measure both (I forgot you had both), you can create your own µW/lumen measurement. There's an entire section in the article on absolute UV values, which was nice to see. Probably a hat tip to radiometry nerds like me.

Based on that article, it does seem like 10-75µW/lumen is the acceptable range, even if the approach is wacky. What matters is that museums have been using this approach for a long time and the numbers hold up, so make use of the numbers. Let's do some math:

1 Lux = 1 lumen/m2

1 m2 = 10000 cm2

Visible light meter reads 4600 lux

UV meter reads 12 µW/cm2

The equation given in the paper looks like this:

UVab = (L x UVr) / 1000, where UVab is reported as mW/m2, but those aren't the units we want. So, this is what you do:

µW/cm2 = (lumen/m2 * μW/lumen) / 10000

So, you end up with 12 = (4600 * UVr) / 10000, where UVr = 26.09 µW/lumen

A value of 26 is in the acceptable range, so my best guesstimate is that your bulbs are fine.

Edited September 13, 2020 by Anasazi37

[MechTech]

About vitamin D. Research shows you should have some exposure to natural sunlight for about 10 to 15 minutes a day. It is not just vitamin D, it helps your eyes too. In fact, recent research shows red light to help your eyes regenerate. Sitting inside all day also causes nearsightedness by your eyes not getting what they need. It kinda sucks. Too much sun breaks you down, not enough screws you up. Nothing is ever simple.

About yellowing. Your problem is not just UV light, you're breathing it in right now. Oxygen will also oxidize plastics without UV light. It's not as simple as keeping them in the dark, but sealed air tight. And that's not the only issue. You can still have issues because plastic formulations vary as much as there are types of cheese! Some plastic is cheap and just destabilizes with time. I've had the same problem with stuff kept in boxes, in the closet, smoke free house, and it still goes yellow. I've studied a lot on plastics and engineer a lot with them. Sometimes you just can't win.

Buy your your toy, enjoy the new toy smell, and then don't get your hopes up too high I'd say. - MT

[Slave IV]

1 hour ago, MechTech said:

About vitamin D. Research shows you should have some exposure to natural sunlight for about 10 to 15 minutes a day. It is not just vitamin D, it helps your eyes too. In fact, recent research shows red light to help your eyes regenerate. Sitting inside all day also causes nearsightedness by your eyes not getting what they need. It kinda sucks. Too much sun breaks you down, not enough screws you up. Nothing is ever simple.

About yellowing. Your problem is not just UV light, you're breathing it in right now. Oxygen will also oxidize plastics without UV light. It's not as simple as keeping them in the dark, but sealed air tight. And that's not the only issue. You can still have issues because plastic formulations vary as much as there are types of cheese! Some plastic is cheap and just destabilizes with time. I've had the same problem with stuff kept in boxes, in the closet, smoke free house, and it still goes yellow. I've studied a lot on plastics and engineer a lot with them. Sometimes you just can't win.

Buy your your toy, enjoy the new toy smell, and then don't get your hopes up too high I'd say. - MT

This. 

[MacrossJunkie]

1 hour ago, MechTech said:

About yellowing. Your problem is not just UV light, you're breathing it in right now. Oxygen will also oxidize plastics without UV light. It's not as simple as keeping them in the dark, but sealed air tight. And that's not the only issue. You can still have issues because plastic formulations vary as much as there are types of cheese! Some plastic is cheap and just destabilizes with time. I've had the same problem with stuff kept in boxes, in the closet, smoke free house, and it still goes yellow. I've studied a lot on plastics and engineer a lot with them. Sometimes you just can't win.

I've also known about the oxidation component, but have always wondered if clear coating helps prevent/slow it down or if the clear coats are too porous to air for it to matter. That's aside from the issue that there are some clear coats themselves that are prone to or notorious for yellowing like Testor's clear coats.

[Anasazi37]

1 hour ago, MechTech said:

About vitamin D. Research shows you should have some exposure to natural sunlight for about 10 to 15 minutes a day. It is not just vitamin D, it helps your eyes too. In fact, recent research shows red light to help your eyes regenerate. Sitting inside all day also causes nearsightedness by your eyes not getting what they need. It kinda sucks. Too much sun breaks you down, not enough screws you up. Nothing is ever simple.

About yellowing. Your problem is not just UV light, you're breathing it in right now. Oxygen will also oxidize plastics without UV light. It's not as simple as keeping them in the dark, but sealed air tight. And that's not the only issue. You can still have issues because plastic formulations vary as much as there are types of cheese! Some plastic is cheap and just destabilizes with time. I've had the same problem with stuff kept in boxes, in the closet, smoke free house, and it still goes yellow. I've studied a lot on plastics and engineer a lot with them. Sometimes you just can't win.

Buy your your toy, enjoy the new toy smell, and then don't get your hopes up too high I'd say. - MT

Agreed, it's not just about UV light. If you have the means, ability, and interest to mitigate it as one of causes, it will help to reduce the odds of yellowing, but there's the nature of the plastic itself and also the atmosphere to contend with, as you say. Oxygen, humidity, temperature, etc. Altitude also has an effect. I live at 6300 feet in a desert, so there's less oxygen and humidity up here, but also less atmosphere, meaning more natural UV gets through. Right now all of my Macross stuff is displayed on open shelves in a room that doesn't get direct sunlight, plus I keep the curtains closed. Good enough for me.  I might upgrade to glass cases at some point because dusting my collection is really annoying.

[vladykins]

1 hour ago, Anasazi37 said:

  I might upgrade to glass cases at some point because dusting my collection is really annoying.

But then what would i do with the makeup brush I stole from my wife?

[tekering]

4 hours ago, Anasazi37 said:

Right now all of my Macross stuff is displayed on open shelves in a room that doesn't get direct sunlight, plus I keep the curtains closed. Good enough for me. 

Not good enough for your toys, I fear... although you may not notice until you've had to pack them up for a while.  

Direct sunlight will have a bleaching effect, but it's the indirect sunlight that does the real damage.  Uneven discoloration is the most prominent and annoying effect, and (not unlike COVID-19) the damage may already be occurring, despite an immediate lack of symptoms.

The only halfway-effective solution to yellowing is an absolute zero-tolerance policy, from the moment the toy is opened: no exposure to sunlight whatsoever!  

[Kanedas Bike]

This discussion is fascinating, a good portion of items that I've had in my collection the longest, Yamato 1/60 v. 2 and Bandai Renewal DX Chogokin Frontier line have been on display for years - from Southeast Florida (as sunny as sunny can be) to Southeast Michigan.

I didn't and still don't do any of the extreme anti-yellowing methods mentioned on this thread and so far I've only suffered (3) toy casualties to yellowing out of about 30 items that have been on display for at least 7-10 years. And all of the yellowing happened in Michigan that is undeniably less sunny that Florida. 

Of the items that yellowed;

1. Bandai DX Chogokin VF-25F in Fighter with Tornado packs, the yellowing occurred because I had it on display on my desk, near a window that faces north, but accepts sun from the east. It was that eastern sun that yellowed that side of the Valkyrie. That one was all on me. 
2. Yamato TV VF-1S Roy, that has partial yellowing on the lower portion of one leg (displayed in Battroid). This item was positioned towards the front of a Detolf shelf on the top shelf. The yellowing is barely noticeable and seems to have arrested by simply moving the item further back on the same shelf. 
3. The one that pains me most is a DX Chogokin VF-1J (displayed in Battroid) that seems to have caught sunlight via reflection through from that same window that accepts eastern sun, reflected from one picture on my wall, to another picture that the Valk happened to be positioned in front of. The yellowing is on the back of the Valkyrie and only on the portion that was in front of that picture.

Personally I try not to worry about it too much, especially as I still collect items to remain MISB and the idea that they're just in a box turning yellow irks me to no end. But I also know that not having my toys sealed in a sunless vacuum isn't a death sentence either.

I'd just say exercise some "common" sense with how you display your toys and do your best to enjoy them while you can (and not worry too much about their eventual degradation or loss of value).

-b.