Daheckizzis?

[The Rat]

Took a look at the shelf today and see this, the red on the decal has completely faded. It wasn't in direct sunlight, and the red on the other decals is also starting to go. They came from the Hobbycraft CF-100 sheet. Not happy. Now I have to either try to ignore it, or replace them, or write another backstory about the Belgian Air Force being supplied with lousy paint, or another backstory involving a mythical nation with the 'new' roundels.

Decal fade by Dave Bailey, on Flickr

[Rheged]

I rather like the "unsuitable paint" concept.  I'm sure that the backstory will be fascinating to read.

[Spey_Phantom]

you could set it outside for a few/weeks days, and build it as a wreck thats been laying abandon for a few years 
maybe on a diorama with some oil barrels,.....

[Captain Canada]

That's bizarre !

[kerick]

As you say it wasn't in sunlight but was it under lights that might have given off a lot of UV light? I'm thinking of flouresent but do LEDs give off a lot of UV also?

[zenrat]

Whatever is causing the fading looks to be coming from above as those on the sides are redder.
What are those on the undersides of the wings like?

[Dizzyfugu]

It's probably indirect UV light from the sun. I have a Macross VF-1, white with red trim, and even though it is not exposed to direct sunlight, the decals on the "front side" in the glass cabinet where it has been for 20 years have faded considerably - also on another Macross mecha (the red in the "kite" roundel), but there it is less obvious.

However, there are real world cases with similar weathering/bleaching which look so weird/strong that noone would try this on a model because it looks "unrealistic". 

[The Rat]

Whatever is causing the fading looks to be coming from above as those on the sides are redder.
What are those on the undersides of the wings like?

Yeah, undersides are fine, so it must be sunlight. Other models on the same shelf, and even more exposed, are okay, so I guess that Hobbycraft used terrible dyes. 

[zenrat]

Red always seems to fade first.  Red cars suffer most under the Australian sun.