Strange red flakes in GI

[LSR]

Hello, I am a newbee corona user. I was testing render and everything was cool, but today at the same very scene some red flakes started to appear at random places.

I can't localize the problem. These flakes appear on a different materials. I tried turning off some lights, but nothing changes.

For lightning I am using 3 corona lights and one plane with corona light material (with gradient texture on it).

[Ondra]

It looks like the slot material is too bright. Try making it darker

[maru]

Looks like normal noise to me. Doesn't it go away after you wait for some more passes?

[borisquezadaa]

Maybe some incompatible material giving headaches?...

[Ondra]

no, it is just GI noise from many bounces of light in the hole

[LSR]

It looks like the slot material is too bright. Try making it darker

Material slot has brightness of 180. Haven't changed it for this test, but I'll try later. My main concern is that there is nothing there in the scene to reflect or illuminate with such intensity.

Maybe some incompatible material giving headaches?...

No, they are all fine simple corona materials. I did many test renders of this scene before without any trouble.

Looks like normal noise to me. Doesn't it go away after you wait for some more passes?

Indeed it does become a less bright, but doesn't go away entirely. And yet again - there hasn't been any red flares before. And there is no reason for this flare to appear. I mean, it's a simple scene, simple materials, what could possibly go wrong ;)

[maru]

Did you change any other Corona settings? Like MSI?

[lacilaci]

what if you try to increase max ray depth to 100? Also what is your max sample intensity?

[Ludvik Koutny]

Do you use glossy refraction for this plastic material?

[maru]

Well it is true that the red flakes are a bit annoying in glossy materials with at least some red colour in reflectivity. But this looks like a feature to me and it will also happen to other colours (not so significant, though).

[maru]

Also visible on a slightly less reflective material:

[LSR]

Did you change any other Corona settings? Like MSI?

For this render it's all the default values.

Well it is true that the red flakes are a bit annoying in glossy materials with at least some red colour in reflectivity. But this looks like a feature to me and it will also happen to other colours (not so significant, though).

Your noise looks fine and even, while i have this one tiny dot of red that bothers me. And i can't undertand why it happens. I tried changing different settings, but it still stays there.

Though it fades away after 100 passes. Maybe I'm being too picky and these flakes are fine... Thanks for the help everyone! I'll continue testing, maybe something interesting will show up.

up. Is it fine that the green value has negative number? I mean. is ok from technical point of view?