milsu Posted July 30, 2007 Share #1 Posted July 30, 2007 Advertisement (gone after registration) I am sure this had been discussed many times, but I have a need to ask once again. So, what's the point of scanning films in 14/16 bit depth TIFF, when the photos are being printed in 8 bit JPEG? Is there any difference if I scan in 14 bit and change to 8 bit for printing, or if I originally scan in 8 bit and print? Quote Link to post Share on other sites More sharing options...
Advertisement Posted July 30, 2007 Posted July 30, 2007 Hi milsu, Take a look here 16/14 bit or 8 bit scans?. I'm sure you'll find what you were looking for!
stunsworth Posted July 30, 2007 Share #2 Posted July 30, 2007 If you scan at 16 bit you can make more 'agressive' adjustments to the file without introducing unwanted effects such as posterisation. If I need to produce Jpegs - for 3rd party printing etc. - then I convert to 8 bit and save as Jpeg as the final stage in the process. I had some 50 6"x4" prints to get ready at the weekend and I created an action in Photoshop to flatten any layers, convert to sRGB and then same to a particular directory, so the final output process can be automated. When the output is to my printer I leave as 16 bit and save as PSD files. Quote Link to post Share on other sites More sharing options...
dfbldwn Posted July 30, 2007 Share #3 Posted July 30, 2007 IIs there any difference if I scan in 14 bit and change to 8 bit for printing, or if I originally scan in 8 bit and print? I don't know if you'll find any difference. When I started scanning at 14 bit, pulling (by TWAIN) into Photoshop, where it acquires 16-bit (well ... Photoshop's 15 bit plus a bit something it feels it needs) I noticed such a large difference that, despite the extra time and trouble, I never scan at 8 bit anymore. I convert back to 8-bit for all printing. The difference is how the same Photoshop manipulations (Levels, Curves, Hue/Saturation, Resample, Interpolate, whatever you do with a scanned image) just work better with 16-bit data than with 8-bit data. To repeat, my 8-bit final output is significantly better when I have done the post-scan processing with a 16-bit image. - David Quote Link to post Share on other sites More sharing options...
j. white Posted July 31, 2007 Share #4 Posted July 31, 2007 To put it simply, think of it like this: The bit-depth refers to the number of bits used to represent each pixel in the image. Thus with an 8-bit file, each pixel can be represented by a range of 256 shades. With 16-bits, that number goes up to over 16,000. It's easy to imagine what this does for subtle gradations between tones in capture, as well as the manipulations mentioned by others, particularly when these values are exaggerated by changes to overall levels and gamma curves. Hope that helps... -J. Quote Link to post Share on other sites More sharing options...
cocker Posted July 31, 2007 Share #5 Posted July 31, 2007 An interesting discussion as I am working my way through 30+ years of negatives and slides (35mm and MF) with a new scanner (Epson V750 PRO - very pleased with it). I am scanning at 16-bit for the reasons Steve and Co. have outlined. I have a question though. Most of my negatives are B & W and I scan 16 bit HDR Greyscale (with Silverfast Ai studio then process the HDR scans through Silverfast HDR Studio). Am I right in thinking the 16-bit advantage for editing in Photoshop applies to Greyscale as well as RGB scans? Quote Link to post Share on other sites More sharing options...
stunsworth Posted July 31, 2007 Share #6 Posted July 31, 2007 Keith, I scan b&w as 16 bit greyscale. I know others scan them as 48 bit RGB, but when I tried that I didn't notice any difference between the two. Plus the RGB files are three times as large as the 16 bit greyscales. I was using Vuescan, perhaps this levels things out if you pardon the pun. In terms of data captured, a 16 bit greyscale file has as much information as a desaturated 48 bit RGB file, but everything is in one channel rather than three identical ones. Quote Link to post Share on other sites More sharing options...
Photoskeptic Posted July 31, 2007 Share #7 Posted July 31, 2007 Advertisement (gone after registration) Keith, I use SilverFast with my Minolta 5400, but I use the 16-bit greyscale, not the HDR. Just curious, did you try them both and find the HDR better or is that the mode you started with and were satisfied with the results? Quote Link to post Share on other sites More sharing options...
cocker Posted July 31, 2007 Share #8 Posted July 31, 2007 Thanks Steve, that's helpful - I was hoping I wasn't sacrificing anything for disc space. John, I choose the HDR route as it seemed - admittedly via the extra expense and additional processing stage of Silverfast HDR - to give more tonal range and control. I'm not the sort to do controlled comparisons but I think it is worth the extra time and expense. Best wishes Quote Link to post Share on other sites More sharing options...
Photoskeptic Posted July 31, 2007 Share #9 Posted July 31, 2007 Thanks, Keith. I've got a roll of Adox 50 to finish this week so I'll give HDR a try. Quote Link to post Share on other sites More sharing options...
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