# vtkColorMaps getPresetByName with vtk.js as external script
**URL:** https://discourse.vtk.org/t/vtkcolormaps-getpresetbyname-with-vtk-js-as-external-script/1183
**Category:** Support
**Created:** [June 20, 2019, 11:24am UTC](https://discourse.vtk.org/t/vtkcolormaps-getpresetbyname-with-vtk-js-as-external-script/1183 "2019-06-20T11:24:13Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@PBrockmann](https://discourse.vtk.org/u/PBrockmann)
#### Post date: [June 20, 2019, 11:24am UTC](https://discourse.vtk.org/t/vtkcolormaps-getpresetbyname-with-vtk-js-as-external-script/1183/1 "2019-06-20T11:24:13Z")
From [https://kitware.github.io/vtk-js/examples/ScalarToRGBA.html](https://kitware.github.io/vtk-js/examples/ScalarToRGBA.html)
there are those lines to preset a lookup table:
```auto
import vtkColorMaps from 'vtk.js/Sources/Rendering/Core/ColorTransferFunction/ColorMaps';
import vtkColorTransferFunction from 'vtk.js/Sources/Rendering/Core/ColorTransferFunction';
const lookupTable = vtkColorTransferFunction.newInstance();
const preset = vtkColorMaps.getPresetByName('erdc_rainbow_bright');
lookupTable.applyColorMap(preset);
lookupTable.setMappingRange(...dataRange);
lookupTable.updateRange();
```
But how to do the same when you use vtk.js as an external script ?
I cannot find how to instantiate vtkColorMaps.
```auto
const lookup = vtk.Rendering.Core.vtkColorTransferFunction.newInstance();
const preset = vtk.Rendering.Core.???????
preset.getPresetByName('erdc_rainbow_bright');
lookup.applyColorMap(preset);
lookup.build();
```
---
### Author:  [@Forrest](https://discourse.vtk.org/u/Forrest)
#### Post date: [June 25, 2019, 2:51am UTC](https://discourse.vtk.org/t/vtkcolormaps-getpresetbyname-with-vtk-js-as-external-script/1183/2 "2019-06-25T02:51:27Z")
Hi Patrick,
This is a missing export. I will add the export in and you should be able to use it shortly like so:
```auto
const vtkColorMaps = vtk.Rendering.Core.vtkColorTransferFunction.vtkColorMaps;
const preset = vtkColorMaps.getPresetByName('erdc_rainbow_light');
```
---
### Author:  [@Forrest](https://discourse.vtk.org/u/Forrest)
#### Post date: [June 25, 2019, 3:23am UTC](https://discourse.vtk.org/t/vtkcolormaps-getpresetbyname-with-vtk-js-as-external-script/1183/3 "2019-06-25T03:23:30Z")
Update: the latest vtk.js version now supports the above export. Let me know if it doesn’t work for you for some reason.
---
### Author:  [@PBrockmann](https://discourse.vtk.org/u/PBrockmann)
#### Post date: [June 25, 2019, 10:58am UTC](https://discourse.vtk.org/t/vtkcolormaps-getpresetbyname-with-vtk-js-as-external-script/1183/4 "2019-06-25T10:58:35Z")
Thank you for the support and action !
It works now.
Also note that ‘erdc\_rainbow\_light’ is now named ‘erdc\_rainbow\_bright’
```auto
var lookup = vtk.Rendering.Core.vtkColorTransferFunction.newInstance();
var preset = vtk.Rendering.Core.vtkColorTransferFunction.vtkColorMaps.getPresetByName('erdc_rainbow_bright');
lookup.applyColorMap(preset);
lookup.setNanColor(1.0, 1.0, 1.0, 1.0); // should be after applyColorMap
lookup.build();
```
To get all preset color maps:
```auto
console.log(vtk.Rendering.Core.vtkColorTransferFunction.vtkColorMaps.rgbPresetNames);
```
