PSP X6 will not open or save 16-bit greyscale jpg

[michael42]

Is this a bug or just not a feature?
Other applications will do this.

[Forriner]

I'm curious, what applications (plural) are you talking about? Jpeg is 24-bits (8 bits per channel), and according to Wiki there's a 12-bit somewhere but I've never seen one.
PSP and Photoshop, for example, reduce 16-bit per channel images to 8 bits if you want to save as jpg. It doesn't matter that there are only 256 colours in that 16-bit grey scale file. By default PSP prompts and asks about reducing, or you can save in a 16-bit format like PSPimage or TIFF.

[michael42]

Before retiring I programmed in MatLab which has a powerful image processing toolbox, which did support 16-bit greyscale jpeg.
I cannot remember which other application supported the format, as I no longer have access to my previous work applications.
It is a lossless format which seems to be an obscure part of the jpeg 2000 standard.
For me it seems an ideal format, I scan 'black and white' film in 16-bit resolution, then edit in PSP and would like to save in a memory efficient format without loosing resolution.

[Forriner]

I do remember reading about specialized jpegs, in hospital MRI images or something like that, but only as a specialism, not something in general use. Strange, would there be patents in the picture?
You can save (Save as... actually, I think Save defaults to 20% compression) JPG and Jpeg2000 with lossless encoding, but both are eight bits per channel. A few versions ago 'lossless' always froze my computer, but it seems to work now (X4 with all service packs). Somehow, 16 million shades of grey would seem enough to me
Good luck in your search, anyway.

[michael42]

8-bits so only 256 shades of grey, which is why I want 16-bit.
Only one channel in greyscale.

[df]

I think you're going to be stuck with 16 bit tiff files. The scanning software isn't making 16 bit greyscale JPEGs and nothing that you'll view it on would read it, you'd just be doing the editing. Memory space is getting cheaper too. I don't see the need to reinvent the wheel for this one. An alternative is to use the color mode on the scanner and save as a regular color JPEG.