POV-Ray : Newsgroups : povray.newusers : White comes out grey Server Time
23 Nov 2024 23:52:12 EST (-0500)
  White comes out grey (Message 1 to 5 of 5)  
From: Marco
Subject: White comes out grey
Date: 4 Jun 2011 06:55:01
Message: <web.4dea0ec46ddba0116731f09e0@news.povray.org>
I have found discovered that applying a color to an object renders it black,
while if I apply a texture, it gets rendered in that texture's basic color.

But I cannot get the object to render in white, it remains a dullish grey even
if I define my own White texture (called Wit, Dutch for White). Here's the
scene: http://home.ooijer.com/povray/color-test.zip (pov and jpg) The difference
can't be caused the lighting, not in this scene, can it?

BTW this is with povwin 3.6.

Please help?


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From: Stephen
Subject: Re: White comes out grey
Date: 4 Jun 2011 07:09:30
Message: <4dea126a@news.povray.org>
On 04/06/2011 11:53 AM, Marco wrote:
> I have found discovered that applying a color to an object renders it black,
> while if I apply a texture, it gets rendered in that texture's basic color.
>
> But I cannot get the object to render in white, it remains a dullish grey even
> if I define my own White texture (called Wit, Dutch for White). Here's the
> scene: http://home.ooijer.com/povray/color-test.zip (pov and jpg) The difference
> can't be caused the lighting, not in this scene, can it?
>
> BTW this is with povwin 3.6.
>

The first thing I notice is you have #version 3.5;
I would change that to #version 3.6; for a start.

Then your Finish is
		finish {
			ambient 0.0
			specular 0.0
			roughness 0.2
		}

Which means that the colour of your sphere is only that of the light 
reflected off it.

Read the help 3.5.3 Finish
And maybe add some ambient and diffuse.

Sorry I can't actually render your scene but I'm running a long 
animation just now.

-- 
Regards
     Stephen


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From: clipka
Subject: Re: White comes out grey
Date: 4 Jun 2011 07:14:03
Message: <4dea137b$1@news.povray.org>
Am 04.06.2011 12:53, schrieb Marco:

> But I cannot get the object to render in white, it remains a dullish grey even
> if I define my own White texture (called Wit, Dutch for White). Here's the
> scene: http://home.ooijer.com/povray/color-test.zip (pov and jpg) The difference
> can't be caused the lighting, not in this scene, can it?

And yet it is.


Your only light in the scene is the parallel one (the other doesn't have 
any effect as it is inside the black sphere), which has a brightness of 0.8.

Your "Wit" texture uses a pigment of brightness 1.0, but as you don't 
specify a "diffuse" value, it uses the default of 0.6 for that. You also 
don't use any specular or ambient term.

The resulting maximum brightness (at the point on the sphere directly 
facing the light source) is therefore

     0.8 * 1.0 * 0.6 = 0.48

which, obviously, is far from 1.0, which would be a fully white pixel color.

Note that a "diffuse" value of <<1.0 is indeed realistic, even for 
"white" materials, as only few materials come even close to this value; 
strictly speaking, a sheet of white paper would have to be called 
"bright grey". The problem, therefore, must indeed be attributed to a 
lack of lighting.


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From: Jaime Vives Piqueres
Subject: Re: White comes out grey
Date: 4 Jun 2011 07:35:35
Message: <4dea1887$1@news.povray.org>

> I have found discovered that applying a color to an object renders it
> black, while if I apply a texture, it gets rendered in that texture's
> basic color.

   Didn't you see the warning when rendering that scene? :

>> File 'color-test.pov' line 72: Parse Warning: Quick color belongs
>> in texture. Color ignored.

   You cannot use the color keyword alone, you need to at least enclose
it on a pigment{}.


> But I cannot get the object to render in white, it remains a dullish
>  grey even if I define my own White texture (called Wit, Dutch for
> White). Here's the scene:
> http://home.ooijer.com/povray/color-test.zip (pov and jpg) The
> difference can't be caused the lighting, not in this scene, can it?

   Read clipka response... lighting is everything! (at least if you don't
use full ambient/emission). It's a mystery to me why do you think
lighting should not affect the perceived color of an object...

   Regards,


-- 
Jaime Vives Piqueres
		
La Persistencia de la Ignorancia
http://www.ignorancia.org


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From: Marco
Subject: Re: White comes out grey
Date: 8 Jun 2011 17:05:00
Message: <web.4defe2eafcf0f40e6731f09e0@news.povray.org>
Hi guys,

Thanks so much for the replies, I learned so much from your posts! I had already
been using poray for quite some time (and quite succesfully as well), so I
consider myself to not be a noob, but you made it clear that I have so much to
learn still. Time to ge back on gthe learning curve I guess... And I've been
working on this scene on and off for such a long time, I lost track of the
changes I made. Big bad omy part, need to focus on 1 thing at a time.
 (p.s. I knew about the light inside the sphere, originally I intended to make a
cutout and make a light shine from inside of it, I just forgot to remove the
light)
And yes, I missed that parse warning, thanks for the heads-up.


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