Best time in work flow to convert from 16 bit to 8 bit?

[photom]

After scanning at 16 bits, what is the best time to convert to 8 bit

to avoid such large and slow files? I assume the main adjustment to

be done first is tonal range related steps? After contrast,

brightness, shadow/highlight, primary color adjustment is done, would

this be the best time to convert and then finish all other work as an

8 bit file(noise reduction, sharpening, cleaning, other misc.

editing)?

[awindsor]

Noise reduction should be done on the 16 bit file before major tonal adjustments.

If you have Photoshop CS then you can use adjustment layers on a 16 bit file and the

pressure to convert to 8 bit is reduced.

[michaelging]

I keep it in 16 bit ,until just before I save it.

[Ed_Ingold]

I recommend you keep the original file untouched. Produce a master image starting with a copy of the original, still in 16-bit mode. Make corrections in adjustment layers if possible. If you spot dust and scratches, it's best to do it in the master file. Save this file as a PSD or TIFF, complete will all layers.

 

For printing, start with a copy of the master file, resize and resample if necessary, sharpen, collapse all layers, rename and save. If you plan to send the image out for printing, change the color space to sRGB. If by cleaning, you mean grain reduction, do this just before sharpening. Cleaning is a destructive process that you may want to change later.

[Uhooru]

Noise Ninja, recommends you reduce noise early in the process not later and before you make you levels/curves/tonal adjustments etc.