Alpha input for colours

Quick question, how does the alpha input work for colours? I understand it’s just a transparency range, however no matter what number I use for it, the elements in Revit remain completely solid. I’ve googled an argb colour picker just to double check, but it still remains solid.

(Ignore the numbers in the above picture, I realise alpha’s disconnected on the first block

Update: I’ve just changed the transparency in visibility graphics. I’m still not sure what the alpha input actually does though

Also is there a way to undo any selection of colour? In the picture below, I want to colour the single AHU in red to show it hasn’t been named yet, and not apply any colours to the other 7 AHU’s. Obviously I can just not attach any colour to the other 7, however when it’s switching from the coloured box to the non-coloured box, the colour remains the same, hence I need to reset the colour to its original

And one more thing, is there a way to colour in every element in a project, rather than just the ones in view?

In Dynamo we can only do what is possible in Revit. The way you override in Revit is a different method. The alpha on the color nodes will primarily work with Dynamo geometry, (to my knowledge).

##Example of this:###

####Transparency API method
http://www.revitapidocs.com/2017/a8803ede-cdc0-31ff-113b-9a3a3b6befe6.htm

####Color API method
http://www.revitapidocs.com/2017/8970811f-f07a-689e-fd1e-de506a5a1b9c.htm

##For the overriding everywhere.##
Short answer = yes it is possible.
Long answer = You will have to look at color override nodes available, collecting the views and applying changes per every view.

@john_pierson I’m not too worried about the views anymore, as I can just put it into 3D so all the correct pieces of equipment are selected. I’ve had a look at the links you sent but I’m not really sure how to use them. Surely there’s a simple solution to reset the colours to their original settings? I’ve had a look through the packages available but haven’t had any luck