Photoshop Tutorial : How To 32 Bits Per Channel Color | Graphicxtras
You can find the Photoshop 32bit mode via the image menu and mode and it is right at the bottom of the menu (32bits / channel). The gradients tool and functions are all there but just even more impressive
Loss of functionality
It gives you a vast range of RGB to choose from but it does come with some cost as some of the functionality is lost either because it makes little sense to have that level of functionality with that vast range of colors or that part of the application is yet to be updated, hopefully in the case of many of the filters and adjustments, all will be available for that color mode. You wil notice that the overlay blending mode and soft light are not available etc
Select the tool
Apply using blending modes such as difference. Select any of the presets in the panel and apply them. You can double click the presets box in the top left and edit the stops etc as with 8bits. Apply the tool multiple times to create stunning designs. Or use the layer menu and new fill layer etc. When you change the stops, you will see a different picker panel with a great range. You can also enter decimals into the red green and blue fields such as 0.22939 etc to create even more subtle combinations in different blending modes. The method of perceptual, linear and classic are also still available via the top control bar.
You will also notice that the picker is different. The blending of gradients is vastly improved and the results with the available blending modes can be totally amazing. Likewise with the application of brush strokes. Even converting back to the more normal RGB 8 bit and you have the HDR toning panel to offer even more color creativity.