Steve Broadbent wrote:
I have been working with CS3 for a while and have never encountered this.

Firstly: I normally do greyscale conversion after RAW processing, but but decided that the job only required RAW processing at the time so i changed the file to grey scale in the RAW conversion process and saved as a jpeg directly from it without going fully into photoshop to play. My problem is, i decided to do some editing on the JPEG in photoshop later and it would only allow me to edit in greyscale and i could not add any colours AT ALL. even in the colour pallet after i selected my colour it turned to grey on the toolbar......

anyway second problem:
Photoshop has suddenly decided not to let me SAVE AS as all the usual files.... it only lets me do TIFF and an assortment of .PSD files. JPEG is gone..... for what seems to be no reason at all. so now i have to resort to "save as for web".

Any help would be greatly appreciated on this. i have worked my way around but it takes so much more time to do it.
thanks
-Steve

Steve,

For the first problem, try changing the color setting to RGB in Image>Mode>RGB Color. That sounds like the issue.

For the second, did you change your BIT setting? You might be in 16 bit mode instead of 8-bit. Image>Mode>8-Bit. Not 100% if that's the issue, but I can only guess from what you have described.

Cheers,
Al

Steve Broadbent wrote:
No wonder the file took so long to open..... it was like, 400+ MB

That must be quite a piece of work to be that big. What did you use to shoot it, The Hubble space telescope? I didn't know it shot in RAW.

Steve Broadbent wrote:
No wonder the file took so long to open..... it was like, 400+ MB

As noted, Grayscale files are only one channel; they don't contain any color information. That said, they also tend to be smaller files for the same bit-depth and pixel count, because they are only one channel instead of 3 (RGB or LAB) or 4 (CMYK).

It's also worth noting that 16-bit files are typically more than twice as large as their equivalent 8-bit files due to the way Photoshop saves them.

And, also as noted, 16-bit files can't be saved as JPEGs. Which is silly, given that layered files can't save the layers as a JPEG, but Photoshop lets you save as a JPEG anyhow, by (temporarily) flattening the file behind the scenes before it saves. It's a long-standing annoyance with Photoshop in that regard, but it persists even in CS4.