Little white artifacts : how to get rid of them ?

[theedge]

Hi,
first of all, I'm sorry for this post because I'm sure this question have already been asked, but I couldn't find which keywords to use to find threads related to it.
So here's my problem :

As you see, in various little areas I have very small zones that are overbright and outlined in black. It is of course very annoying. Could you tell me what causes this and how to prevent it ?
Thanks a lot for your help.

[instinct]

this is due to using a sharpening image filter. Try to avoid them (simply said, they got negative values in their filter curves. VERY bright spots (like sun reflections) get multiplied by that and hence turn black instead.)

Regards,
Thorsten

[theedge]

Ah ok I see. That's too bad as i like the overall look of the render with sharpening image filters. I'll try to stick with softening ones and work out sharpening in photoshop.
Thank you instinct

[vlado]

The bright spots are reflections/hilights from the sun. You can also use the clamp output/subpixel mapping options in the Color mapping rollout to deal with the issue.

Best regards,
Vlado

[theedge]

Ok, let me see if I'm starting to understand this part of of v-ray now :
If I enable color clamping, then it would be pointless to save my image as exr float, as any value beyond 1.0 would simply be ignored. Right ?

[instinct]

yes and no. Yes all values beyond 1 would be clamped. Wich doesnt mean float would be pointless. The color-depth between 0 and 1 is still a LOT higher then with 8 or 16 bit. Actually mathematically there are more possible values between 0 and 1 then between 1 and Infinity with Floating Point hehehe

Regards,
Thorsten

[theedge]

Oh yes ! I missed that point instinct ! there are indeed only 255 possible values between 0 and 1 in the 8 bit format, while there are much more in 16 bits (256x256) and even more in 32 bits

[glorybound]

invisible

That usually goes away for me when I make my sun invisible