On 2/6/07, David Weiss <[EMAIL PROTECTED]> wrote: > 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?
I cannot speak for Elements, but both Photoshop CS and CS2 have extensive 16-bit support. Not all functions are 16-bit ready, but a very useful subset of them are. JPEGs are 8-bit only. However, the advantage of 16-bit image manipulation is not in the end product. It's what happens in between. My workflow is follows: 12-bit PEF raw file from camera->16-bit native Photoshop file, Pro Photo RGB colorspace->edits, adjustments, etc.->conversion to output form/profile (sRGB jpeg 8-bit for web, other formats/colorspaces as necessary for printing) > Secondly, is the difference between 8 and 16 bit editing likely to be > seen in 4x6 prints? In a word, possibly. It all depends on a lot of factors. In my example above, I have a 12-bit raw file, being converted to a 16-bit image file in a VERY large colorspace. If I were to make that an 8-bit file, there is a good chance that any adjustments like curves/levels/etc. could cause posterization. If you look at the histogram of a "normal" image, and it looks like the teeth of a comb, this is what you're seeing. It's usually most noticeable in either shadow or highlight areas, but sometimes it can be seen as an overall degradation of tonality in the image. So it's not a question of large vs. small prints, it's a question of adjustments and tonality. In general, the wider the color space you're working in (sRGB being the narrowest, and the default for web images. Adobe RGB is wider, Pro Photo RGB is wider still), the more you're going to want to have the higher bits-per-pixel. As I indicated above, what I'll do once I have the image in the form I want it, is to convert it back to an 8-bit image, in the correct color space (another thing that the Gimp cannot do, without going to a beta at this point). Photoshop does this all very close to seamlessly. I wish there were an OSS solution that would come close. I would look at it in a heartbeat. Maybe in the 2.4.x version of Gimp, that will get better. -Mat -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
