How to work with 16bit values?

Hello,

I like to work in a real 16bit (per channel) RGB mode.
When I create a new RGB image with 16bit there are only 8bit values (0-255 and not 0-1023) in the color picker and in my info panel.

Is PS CS2 just working internally with 16bit and doesn't provide manual access to all values??

thanks,
mH

First you really have to have a full understanding of bit depth and bit color.
Do a little research.

When you see 8 vs. 16 bit, it's referring to the depth of each channel (e.g., R, G, and B). So an 8-bit file is "24-bit color" (8 bit x 3 color channels) and a 16-bit file is "48-bit color". (16 bit x 3 color channels)

24-bit color gives 256 tones in each color which is more than enough for human vision to see pretty continuous tones. The problem is when you start doing image manipulation you are doing math with those pixel values. Every operation you perform loses information from the bottom few bits due to rounding, especially if you make some serious changes to contrast and color balance like you often need to in processing a film scan. With 48-bit color with 16-bit precision you can loose those last few bits to image manipulation and still have more than 8-bits of real data left for output. Performing the same operations in 8-bit quite often would yield to gaps in the spread of values on the histogram which corresponds to posterization (stepping) on the image.

Edited cause I'm a bonehead

thanks tornupinside for replying,

i know the terms of 16 and 48bits and we video guys are using the 'per channel' term.

some details of my problem:

i will have to work (with photoshop CS2) on a image that will be converted from a logarthmic film scan (cin or DPX) to an image in linear colorspace with 10 or 16 bit (for EACH channel).

I need to see the real values from 0 to 1023 for the pixels like in my compositing software.
photoshop only shows 0 to 255 even if it is a 16bit (per channel) image.

How can i see the real values in photoshop?

thanks,
mH

[QUOTE=moonhopper]thanks tornupinside for replying,

i know the terms of 16 and 48bits and we video guys are using the 'per channel' term.

some details of my problem:

i will have to work (with photoshop CS2) on a image that will be converted from a logarthmic film scan (cin or DPX) to an image in linear colorspace with 10 or 16 bit (for EACH channel).

I need to see the real values from 0 to 1023 for the pixels like in my compositing software.
photoshop only shows 0 to 255 even if it is a 16bit (per channel) image.

How can i see the real values in photoshop?

thanks,
mH[/QUOTE]


I think, you can not see values in 16bit format in Photoshop.
It always conwert all valuse to 0-255 range.

Franly speaking, the Photoshop use 16 bit for saving and calculation, but significant are 15 only.
The 16th bit uses as "warning for out of gamut".