I have added an HDRI image to an Environment light and want to convert it from a coloured image to a greyscale image. Is there a way to desaturate the image from a setting on the light, or by adding a node to the light, like something to perform colour correction on the image?

Is there a color correction node for hue, saturation, etc in Houdini?

You can do color correction in a composite network. The env light's texture path can reference the composite node with ‘op’ syntax. e.g.: op:/img/copnet1/HDR_CC_OUT. The output of the composite will be stored embedded in the ifd.

@jsmack

Thanks for your reply. I am new to Houdini, so your solution is a bit beyond me at present. Could you give more details on exactly what nodes to us and how to link the parameters?
Thanks

You might want to watch this SideFX tut - it doesn't answer your question directly, but it will help you become familiar with Houdini compositing and it's only 6 mins long.

In the tut, they are ‘switching’ to a composite network that is inherently available.

Another option to get into a composite network is to TAB for a COP2 network, which once inside is the same as the one gone into like the tut. (It's different in the sense that it lets you organize your work differently); The same as one can either use the ‘inherent’ Material network, or lay down a node that is also a Material Network.

Once inside a composite network you can TAB a menu for nodes that are specific for composite network; There is a color section that will give you the nodes that lets you do what you need.

In the tut, don't mind that it is being done with an older version of Houidni, it is still relevant even though the node look different.

https://www.sidefx.com/tutorials/making-normal-maps-with-cops/ [www.sidefx.com]