POV-Ray : Newsgroups : povray.general : Image_map question : Re: Image_map question Server Time
30 May 2024 09:50:29 EDT (-0400)
  Re: Image_map question  
From: Alain Martel
Date: 25 Nov 2023 13:08:50
Message: <65623832$1@news.povray.org>
Le 2023-11-25 à 07:29, David Kraics a écrit :
> I keep running into an issue. I image_map a jpeg onto a box. In the image
> created, the jpeg's lines are greatly faded. Darkening the jpeg doesn't improve
> this. Am I missing something? The one I am currently using is;
> 
> 
>   box{<-.5,0,0>,<.5,3.097,.45>
> 
>    pigment{
>      image_map{jpeg"tower.jpg"}
>      scale<1,3.097,1>
>      translate<-.5,0,0>
>      }
>   }
> 
> The scale is to match the box it is on.
> The original jpeg is a blueprint with firm solid black lines. The image is
> greatly faded. Am I missing a function or someting?
> 
Some things that you may try :
Adding a gamma value to the pigment. Try values more and less than 1.
Adding a layered pigment with a transmit value larger than 1 above that 
pigment.

box{<-.5,0,0>,<.5,3.097,.45>

   pigment{
     image_map{jpeg"tower.jpg"}
     scale<1,3.097,1>
     translate<-.5,0,0>
     }
// Add this
   pigment{rgbt<0.5,0.5,0.5,1.5>}
  }

A transmit of more than 1 increase the contrast, and the 0.5 make areas 
with a value less than 0.5 darker and the area with a value larger than 
0.5 brighter. There are a few sample scenes that illustrate this.

Some other things to look for :
If the black is not pure black, an ambient value that is set to large in 
a #default statement can be an issue.
Also, to much light illuminating the box tend to wash out things.
Make sure that the black is really black : RGB <0,0,0>


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