On Feb 6, 2007, at 5:44 AM, David Weiss wrote: > Okay, naive non-programming/non-electrical engineer question here: > > Is Photoshop, Elements or otherwise, a 16-bit editior? I seem to > remember that some features are and some features are not? Please > clarify. If not, is your work around to shoot in raw and use raw > editors and then save in what format? Are there 16 bit jpegs?
All of the important functions that involve serious manipulation of tonal values ... Curves and levels, colorspace conversions, etc ... can be performed in [EMAIL PROTECTED] using Photoshop after v7, recent versions of Photoshop Elements (v3-5), Lightroom, and other tools. PS CS2 has broader 16bit support than PSE5. Lightroom is entirely 16 bit, i believe: I think it does an implicit up-sampling to 16bit even when handed 8bit files in TIFF or JPEG format. My workflow in PS CS2 or Lightroom starts from the RAW file ([EMAIL PROTECTED] capture) and is only rendered to an [EMAIL PROTECTED] RGB file when I output JPEGs for the web or tell whichever program I'm using to print ... the 16bit -> 8bit conversion is done at the application to print driver interface. I only rarely use filters or plug-ins that require reduction to 8bit. > Secondly, is the difference between 8 and 16 bit editing likely to be > seen in 4x6 prints? Print output sizing has little to do with channel depth. The channel depth has everything to do with how much editing overhead you have to work with. With 8bits per channel, that's only 256 discrete values per channel you can work with. Quantization errors from doing tonal curve manipulations and such add up, data loss happens all over the place unless you work carefully. This is called "editing fragility". Move to 16bit and you have far less fragility ... you can make much finer tonal corrections without running into clipping and quantization errors. If you have good exposures and average scenes, do relatively minimal editing, the differences are small if visible at all. If, however, you are working with difficult lighting ratios and need to do a lot of editing, the advantages of 16bit become essential. Like with almost anything else, if what you're doing to make your prints is satisfactory to you, no need to do differently. However, once you start working with more sophisticated software and educate your eye to see the differences in rendering quality, it's hard to go back to less capable image formats and rendering tools. I worked for quite a while in digital image processing using only [EMAIL PROTECTED] (or less!) image formats and tools ... let's say from 1984 to 2003. Once I started getting serious and moved up to cameras that would deliver RAW data at greater bit depths, I became accustomed to the quality possible and now find it hard to go back to older JPEG/TIFF files or tools that do not support the increased bit depth at my disposal. Godfrey -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
