# Variations of black **URL:** \ **Category:** General\ **Created:** [February 23, 2007, 4:41pm UTC](https://forums.chaos.com/t/variations-of-black/29651 "2007-02-23T16:41:43Z")\ **Posts on this page:** 11\ **Page:** 2
**Author:** ![joe\_b](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/joe_b/32/38915_2.png) [@joe\_b](https://forums.chaos.com/u/joe_b)\ **Post date:** [March 10, 2007, 10:52pm UTC](https://forums.chaos.com/t/variations-of-black/29651/21 "2007-03-10T22:52:19Z")
Re: Variations of black I’m not sure if this is a hack or not, but I generally will just boost the IOR of my fresnel up a bit to get strength back in my reflections when making black reflective materials. But I’m not sure if thats physically correct or helpful in this situation. ---
**Author:** ![Micha\_cg](https://avatars.discourse-cdn.com/v4/letter/m/258eb7/32.png) [@Micha\_cg](https://forums.chaos.com/u/Micha_cg)\ **Post date:** [March 10, 2007, 10:56pm UTC](https://forums.chaos.com/t/variations-of-black/29651/22 "2007-03-10T22:56:52Z")
Re: Variations of black Are the reflections the problem or the diffuse color? If reflections are a problem, than I would disable all lights and set a reflection environment only. Than, a fresnel reflection is seted, the rendered image should show a reflection independent from the diffuse color. ---
**Author:** ![dalomar\_cg](https://avatars.discourse-cdn.com/v4/letter/d/aeb1de/32.png) [@dalomar\_cg](https://forums.chaos.com/u/dalomar_cg)\ **Post date:** [March 10, 2007, 10:57pm UTC](https://forums.chaos.com/t/variations-of-black/29651/23 "2007-03-10T22:57:29Z")
Re: Variations of black All my reflections are almost completely mirrors or chrome or 100% or whatever you want to call it…either way the reflection strength is up there. Its hard to talk about “physically correct” when it comes to dark scenes/materials because our eyes adjust to things so much. This seems like more of a artsy kind of thing, so my inclination is the notion of “physically correct” could be thrown out the door…(unless you want to use a physical camera with a 10sec shutterspeed :)) ---
**Author:** ![Travis\_Serio\_cg](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/travis_serio_cg/32/58754_2.png) [@Travis\_Serio\_cg](https://forums.chaos.com/u/Travis_Serio_cg)\ **Post date:** [March 11, 2007, 3:00am UTC](https://forums.chaos.com/t/variations-of-black/29651/24 "2007-03-11T03:00:30Z")
Re: Variations of black The ground plane material should be reflective and should be black, so it reflects the objects in the scene but it will not reflect light at all. i see what you’re saying about the filter color, but i would be inclined to think that this is a glitch and not a mechanic of the application. if it was a mechanic of the app its the only render app that does this, and for what reason would you want it to do that? the object should be able to be RGB 0 and still be able to be specular. the values in this test render are not 0 either, i belive they are around 10 to 12. Even at 10 to 12 that is still no black hole black, so thats what i dont get. If it was a mechanic then i can see RGB 0 functioning this way, but apparently theres a threshold value that is unknown to man and undocumented. ---
**Author:** ![Travis\_Serio\_cg](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/travis_serio_cg/32/58754_2.png) [@Travis\_Serio\_cg](https://forums.chaos.com/u/Travis_Serio_cg)\ **Post date:** [March 11, 2007, 3:02am UTC](https://forums.chaos.com/t/variations-of-black/29651/25 "2007-03-11T03:02:42Z")
Re: Variations of black > [@Micha](#): > > Are the reflections the problem or the diffuse color? If reflections are a problem, than I would disable all lights and set a reflection environment only. Than, a fresnel reflection is seted, the rendered image should show a reflection independent from the diffuse color. hey micha, its the light reflections, not the object reflections that is not working for me. the closer objects move to black the more they lose their specular highlights, or direct light reflections. ---
**Author:** ![dalomar\_cg](https://avatars.discourse-cdn.com/v4/letter/d/aeb1de/32.png) [@dalomar\_cg](https://forums.chaos.com/u/dalomar_cg)\ **Post date:** [March 11, 2007, 6:15am UTC](https://forums.chaos.com/t/variations-of-black/29651/26 "2007-03-11T06:15:19Z")
Re: Variations of black So, I was thinking. What if the reason why the black colors in Vray get “sucked up” is because of how it handles darkness, or in other words early termination. The idea behind early termination is great: basically dark areas (ie shadows and darker materials) can deal with less sampling, and this is a great way to cut down on “unnecessary” calculations and make rendering faster. But in this instance, we want that extra information because it may help bring out more details into our black materials. So what if we tell vray that we want to make the calculation more accurate. Maybe by adjusting some of the QMC Sampler parameters we can do this. Here’s what I suggest: Adaptive amount=.65-.45, Noise threshold= \<.005, min samples= \>12. It may kill render times ;D, but who knows. I’ll try it overnight and see if there is any difference and if this might be a good way to do darker scenes. ---
**Author:** ![Micha\_cg](https://avatars.discourse-cdn.com/v4/letter/m/258eb7/32.png) [@Micha\_cg](https://forums.chaos.com/u/Micha_cg)\ **Post date:** [March 11, 2007, 8:17am UTC](https://forums.chaos.com/t/variations-of-black/29651/27 "2007-03-11T08:17:24Z")
Re: Variations of black > [@Travis Serio](#): > > > [@Micha](#): > > > > Are the reflections the problem or the diffuse color? If reflections are a problem, than I would disable all lights and set a reflection environment only. Than, a fresnel reflection is seted, the rendered image should show a reflection independent from the diffuse color. > > hey micha, its the light reflections, not the object reflections that is not working for me. the closer objects move to black the more they lose their specular highlights, or direct light reflections. Good, now I understand. I would say it is a bug. The clear finish (fresnel) of a material should be totaly independent from the diffuse layer color. So it works in the real world. I test it at the last r4 beta: it works fine here, no bug. The same at R3. If you like to see a highlight of a light, than you must set a glossienes below 1, because a point/light is infinite small and only a little blur make it visible. Joe, if I set a radius for a point light, should this point light not be visible at surfaces with glossieness 1 too? Could somebody test it at 3ds max? Logical it should work so. ---
**Author:** ![joe\_b](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/joe_b/32/38915_2.png) [@joe\_b](https://forums.chaos.com/u/joe_b)\ **Post date:** [March 12, 2007, 1:39pm UTC](https://forums.chaos.com/t/variations-of-black/29651/28 "2007-03-12T13:39:10Z")
Re: Variations of black > [@Micha](#): > > I test it at the last r4 beta: it works fine here, no bug. The same at R3. If you like to see a highlight of a light, than you must set a glossienes below 1, because a point/light is infinite small and only a little blur make it visible. > > Joe, if I set a radius for a point light, should this point light not be visible at surfaces with glossieness 1 too? Could somebody test it at 3ds max? Logical it should work so. If Travis was using the default plastic it has a highlight gloss of 1.0 - so that is probably why there is no highlight visible. What radius are you talking about - shadow radius? ---
**Author:** ![Micha\_cg](https://avatars.discourse-cdn.com/v4/letter/m/258eb7/32.png) [@Micha\_cg](https://forums.chaos.com/u/Micha_cg)\ **Post date:** [March 12, 2007, 7:04pm UTC](https://forums.chaos.com/t/variations-of-black/29651/29 "2007-03-12T19:04:20Z")
Re: Variations of black Yes, if the light source get a radius, than this radius shoud be shown at the highlights. And the glossieness would deteminate the blurieness of the “reflected” disk. At the moment, all lightsources of a scene show the same highlight independent from the radius of the light source. Maybe this is not implemented at Vray yet, but I think, so should it work. ---
**Author:** ![joe\_b](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/joe_b/32/38915_2.png) [@joe\_b](https://forums.chaos.com/u/joe_b)\ **Post date:** [March 14, 2007, 1:50pm UTC](https://forums.chaos.com/t/variations-of-black/29651/30 "2007-03-14T13:50:24Z")
Re: Variations of black > [@Micha](#): > > Yes, if the light source get a radius, than this radius shoud be shown at the highlights. And the glossieness would deteminate the blurieness of the “reflected” disk. At the moment, all lightsources of a scene show the same highlight independent from the radius of the light source. Maybe this is not implemented at Vray yet, but I think, so should it work. I was under the impression that the shadow radius had to do with soft-shadows - I’m not sure how that plays into highlights? ---
**Author:** ![Micha\_cg](https://avatars.discourse-cdn.com/v4/letter/m/258eb7/32.png) [@Micha\_cg](https://forums.chaos.com/u/Micha_cg)\ **Post date:** [March 15, 2007, 2:36pm UTC](https://forums.chaos.com/t/variations-of-black/29651/31 "2007-03-15T14:36:09Z")
Re: Variations of black The radius show not any effect to the highlights. i know this effect from renderman renderers too. But, maybe Vlado could implement that the highlights show the radius of the light source. [Previous page](https://forums.chaos.com/t/variations-of-black/29651.md?page=1)