On Jan 7, 2007, at 7:09 AM, Cory Papenfuss wrote: > A few ways around that data loss: > - Use 16-bit gamma RGB. There's still *some* data manipulation in > terms > of quantizing (rounding up/down), but 12-bit linear has less > gradations > in all areas than 16-bit gamma. > > - Keep all images 16-bit linear and use color-management during any > processing to gamma-correct for viewing. Only convert to > gamma-corrected images for "prints"... web, etc. The master RGB > image > stays in 16-bits.
I'm not entirely certain what you are suggesting, Cory. What is "16- bit gamma RGB"? I've never heard of that. And besides, what the sensor captured is 12bit linear data ... you can never have more gradations than were there, all transformations will have losses, mathematically speaking. There may be more values but they are synthesized in interpolation. You have to do gamma correction in RAW conversion to have a properly rendered image, and data loss in RAW conversion is unavoidable: it is mathematically impossible to do the conversion without it. The process of interpolation (compression of high values and expansion of low values to suit the curve normal to vision) will change original values at the photosites into something else, and some data will be lost in that transformation. Data loss isn't always bad, it is actually necessary to the process; the goal is to lose as little *significant* data as possible. Of course, moving to as large a data space and gamut as possible will maximize what you keep and present the greatest number of options for further editing. All my RAW conversion is done into ProPhoto RGB now, the largest possible color gamut, represented as full [EMAIL PROTECTED] RGB images. I only do downsample conversion to [EMAIL PROTECTED] and sRGB gamut for web display, and all printing is color managed through the appropriate profiles at time of printing. Godfrey -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net
