MP-57 Masterpiece Skyfire Soars Supreme

[danny-boy]

Is there any sunlight that gets in at all? Because in my experience, even the tiniest sliver of sunlight can photodegrade toys. In 2016 I moved my toys to a new TF room where 99% of incoming sunlight is blocked out. But just recently I looked at my Jetwing Optimus Prime toy, which was standing near where a tiny sliver of light comes in and doesn't even directly hit any toys... and his smokestacks were yellowed. If you look at my Bayformers Optimus Prime vs Megatron TFTM re-enactment, you can see his yellowed smokestacks. Since then not only have I painted the smokestacks silver, but I've also added an extra layer of brown paper over that small gap where that sliver of light gets in. Note that this sliver was still obstructed by a closed blind and drape, but there was light bleeding from the very top near the ceiling that would bounce off the ceiling and onto the toy. I've blu-tacked the top of the brown paper onto the ceiling so that it now covers that offending top gap. In short, your toy room should be like a dark room... and then even darker. Dark enough to develop film.

I have learnt the hard way that any amount of sunlight that creeps into a toy room, no matter how small, can discolour toys. Now I got MP Ratchet after I moved, and that toy has never yellowed at all. Only DOTM Optimus Prime had some yellowing, but only because that toy sits on a ceiling high top shelf near where the light was leaking in from. And even then, only the rubber smoke stacks yellowed; no other part, and no other toys. Not even my CHUG Sixshot and Horrorcons who have white and light-grey coloured parts and are also near that ceiling corner. I'm going to add another layer of paper over that existing layer just to make it even darker.

If you can, consider UV tinting your room windows, but yeah, definitely block out all incoming sunlight from any windows. Aside from DOTM OP's smokestacks, I have experienced zero photodegradation since 2016.

Do you mean natural day light entering the room? Because directly opposite the display there’s a window about 6 metres away. Direct sunlight only gets as far as 1 metre in.

[GoktimusPrime]

Do you mean natural day light entering the room? Because directly opposite the display there’s a window about 6 metres away. Direct sunlight only gets as far as 1 metre in.

Believe me, that's more than enough to photodegrade your toys, even if they're not in the direct path of the sunlight. The sunlight was only getting a few cm and it was enough to yellow the smokestacks on my Jetwing OP.

Here is what the window looks like...

Left: Window's location in my TF room with the semi-exposed part circled. It's really small and tucked into that corner, and yet it was still enough to do some damage, but only to the toy sitting right next to it. None of my other toys have been affected.
Centre: Close-up of the semi-exposed area. As you can see, I've covered it up with a cloth-wall hanging poster and even stuck some pieces of cardboard on the top to shield light from coming through the top gap. You can also see the brown paper sheet that I've recently added; that's attached to the ceiling's skirting. I'm going to attach a second sheet of brown paper to cover that remaining gap and produce complete darkness.
Right: This is a window in a different room, but it's the exact same style and size as the one in my TF room. It comes with a solid roller-blind which works well in blocking out sunlight, but as you can see, without any additional obstructions, the sunlight still shines through around the edges, creating a rectangular halo. It's the upper halo (highlighted in yellow) that I hadn't adequately blocked off before and caused yellowing.

So in my experience, you need to block out ALL sunlight, because even indirect ambient natural sunlight that gets into the room can still yellow plastic. It should be blocked out so well that if you walk into the room in the middle of a sunny day with the lights off, it should be pitch dark as if it's midnight. This is what I had achieved except for that tiny top corner, but that little corner with just a limited amount of soft ambient sunlight was still enough to cause damage! You've gotta treat your toys as if they're even more heliophobic than vampires!

[Jetfire in the sky]

Do you mean natural day light entering the room? Because directly opposite the display there�s a window about 6 metres away. Direct sunlight only gets as far as 1 metre in.

I can tell you hand to heart, ANY natural light direct or indirect will F-up the colour of your toys eventually, grey around 1986 onwards and almost any white will degrade. There is a temperature/humidity factor in a darkened room as well.