why after opening photos from RAW into 16bit/channel, i cannot modify / add layers?

[Blackgoddess]

Hi seniors,
got a question which i've been bugging me for quite a bit. I know taking shots in RAW will maintain the most data in the picture etc because it has like 14 - 16 bits/ channel as compared to JPEG which has 8 bits/channel. But after i open my RAW in ACR in 16 bits/channel, i cannot add layers, cannot add adjustment layers and many options for editing the picture is 'locked' and i cannot choose it? It's only after i change the picture to 8bits/channel or i open the RAW in ACR in 8 bits/channel that the full spectrum of editing functions in photoshop is available?

Is there an option i forgot to tick or is the editing functions only available in 8 bit/channel? :think:

 

[sinned79]

u can only edit in 8 bits.

 

[foxtwo]

I can edit in 16bit. Just the majority of filters are disabled, I never touch those anyway so it's fine. Does it have to do with which version of PS you're using? CS4 x64 here.

 

[daredevil123]

I can edit in 16bit. Just the majority of filters are disabled, I never touch those anyway so it's fine. Does it have to do with which version of PS you're using? CS4 x64 here.

Same for CS5 32bit...