The name universal developer is used for developers that can be used to develop film or paper. Rodinal and its variations are universal developers in that sense.
But I intend to make a developer that can be used for B&W and color films and for B&W paper. For color paper I think it will not work, but one may try too.
I could develop a little color using only a homebrewed parodinal. This showed me that it is a base for the future universal developer I want to reach. The photo below was developed with a 1:25 solution of my parodinal and a very small amount of the color developer CD4. This amount is only 0.2g pro 500ml work solution. The only pictures I developed until now exhibit a very warm color, like this:
After this result, I am now preparing a batch of «Colordinal», a concentrate developer to be used like Rodinal, in 1:25, 1:50, 1:100 solutions and that can be used to develop B&W and color films and B&W paper. Basically I replaced a part of Paracetamol with CD4. The solution was prepared yesterday and can be used soonner next Tuesday.