FW: 8 bit vs. more bits No. 2
FW: 8 bit vs. more bits No. 2
- Subject: FW: 8 bit vs. more bits No. 2
- From: "Mark Rice" <email@hidden>
- Date: Sun, 17 Apr 2005 21:06:28 -0400
- Organization: Zero One
Picking up from previous post:
However, this is rarely the case for two reasons:
A. Almost...
B. Every edit that is done on an 8-bit image is skating on very thin
ice. We often see images that have a pre-edit table vs. post edit table that
looks something like this:
Pre-edit Post-edit
245 246
246 246
247 246 (rounding errors)
248 248
249 250
250 252
251 253
252 254
253 255
254 255
255 255 (clipping!)
This can result from a mild edit. Color management is an edit in effect -
and a 3 dimensional one at that!! After color management has passed through
several conversions, and then passed through retoucher's edits, the above
scenario is mild indeed.
So the argument for 16 bit is very strong if any editing is to be done. 16
bits per color, or 48 bits, gives 128,256,000,000 colors, so 16 bit is
adequate for anything that will be converted to 8 bit as the final output.
My opinion is that 32 bit per color data is only useful for HDR imaging,
where cameras are specifically providing 22 - 25 bit output.
But always remember that dithering is one of the most important features of
any output device, and this is only a work around for the fact that bit
depth is never equal to the number of lines in an image.
Hope I didn't bore you with this rant.
Mark Rice
email@hidden
www.zero1inc.com
Today's Topics:
1. RE: 16 bits = 15 bits in Photoshop? (michael shaffer)
2. Re: 16 bits = 15 bits in Photoshop? (email@hidden)
3. Re: 16 bits = 15 bits in Photoshop? (Robert L Krawitz)
4. Re: 16 bits = 15 bits in Photoshop? (Marco Ugolini)
5. Re: 16 bits = 15 bits in Photoshop? (Jim Rich)
6. Re: 16 bits = 15 bits in Photoshop? (email@hidden)
7. Re: 16 bits = 15 bits in Photoshop? (email@hidden)
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