Quoting David Purdie: > I have seen the benefits of converting to 16 bit for manipulation. > > When working on a grayscale image where I had burned in the sky and > corners ( only a little) , I was getting severe posterisation. > Converting the 8 bit file to 16, burning the sky and corners, then > converting back to 8 bit produced a far superior gradation. > > This was clearly visible in prints, not just a theoretical benefit.
David: This reduction in posterization is a result of the "dithering" that is introduced when you move from 16-bit to 8-bit in Photoshop. I posted a set of instructions yesterday, that you can use to test and see the results. Most likely you could have done your manipulations, seen the posterization, converted to 16-bit, then done a second conversion back to 8 bit and the posterization would have disappeared. This doesn't prove that taking an 8-bit image into 16-bit makes for better image manipulation, it simply means that the dithering introduced is helping to smooth out the tonal transitions. David -- Creating an image database? visit (http://ControlledVocabulary.com/) and join the discussion list, or read areview of the Image Info Toolkit utility at: (http://ControlledVocabulary.com/imagedatabases/imageinfotoolkit.html) David Riecks http://www.riecks.com - http://zillionbucks.com =============================================================== GO TO http://www.prodig.org for ~ GUIDELINES ~ un/SUBSCRIBING ~ ITEMS for SALE
