# "Overexposure" in Volume rendering

**URL:** https://discourse.vtk.org/t/overexposure-in-volume-rendering/14360
**Category:** Support
**Tags:** code
**Created:** [August 6, 2024, 8:03am UTC](https://discourse.vtk.org/t/overexposure-in-volume-rendering/14360 "2024-08-06T08:03:08Z")
**Posts on this page:** 3
**Page:** 1

<div class="post-metadata">

### Author: ![Hedwig\_Huang](https://discourse.vtk.org/user_avatar/discourse.vtk.org/hedwig_huang/32/7745_2.png) [@Hedwig\_Huang](https://discourse.vtk.org/u/Hedwig_Huang)
#### Post date: [August 6, 2024, 8:03am UTC](https://discourse.vtk.org/t/overexposure-in-volume-rendering/14360/1 "2024-08-06T08:03:08Z")

</div>

![image](https://discourse.vtk.org/uploads/default/original/2X/d/d09048dad20ea09159362ac8243c2e0960ed7383.png)  
I tried to edit color in the image, but I found that seems some “over exposure” in the 3D picture, could you please tell me which parameters will affect this? Great Thanks!

---

<div class="post-metadata">

### Author: ![Hedwig\_Huang](https://discourse.vtk.org/user_avatar/discourse.vtk.org/hedwig_huang/32/7745_2.png) [@Hedwig\_Huang](https://discourse.vtk.org/u/Hedwig_Huang)
#### Post date: [August 12, 2024, 2:07am UTC](https://discourse.vtk.org/t/overexposure-in-volume-rendering/14360/2 "2024-08-12T02:07:53Z")

</div>

seems some light parameters or something is too much?

---

<div class="post-metadata">

### Author: ![Hedwig\_Huang](https://discourse.vtk.org/user_avatar/discourse.vtk.org/hedwig_huang/32/7745_2.png) [@Hedwig\_Huang](https://discourse.vtk.org/u/Hedwig_Huang)
#### Post date: [September 10, 2024, 1:13am UTC](https://discourse.vtk.org/t/overexposure-in-volume-rendering/14360/3 "2024-09-10T01:13:11Z")

</div>

The problem is fixed by changing mapper’s class. I tried to use `vtkFixedPointVolumeRayCastMapper` instead of `vtkGPUVolumeRayCastMapper`, then worked.  
But the property of color for `AddRGBPoint` seems not very similar, but this problem can be caused by the ambient and light settings.