Archival scans, 48bit, Nikon Coolscan 5000 ED, ? Gamma 1.0 ?

Hi All,

I wish to scan ~3-4000 slides, for two reasons, one to have the images available electronically but mainly to have a safe archive/backup of the images (most of these slides cover the period when I used to work for the British Antarctic Survey, are c20 years old and I would be gutted if I lost them…).

I’ve had a Nikon Coolscan 5000 ED for a couple of months, and have spent the time becoming familiar with it…. and colour management. On the colour management issues I am now just starting to get a good overall idea of how things work (and I must admit it was not simple, and I am speaking as a lapsed physicist!).

I would like to scan these slides ONCE – i.e. I would like to get it right the first time. I intend to scan at 48bits and 4000dpi (i.e. the max resolution of the scanner).

Can anyone comment on the scenario below:

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* 16bits/channel / 4000dpi
* Raw scanner RGB at – gamma 1.0 – (Nikon colour management turned off). * Only processing performed by the scanner being digital ICE * Scanner calibrated using it8 targets and resultant icc profiles used to perform conversion to the working colour space (presently Wide Gamut RGB) on import of the raw gamma 1.0 files to Photoshop

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I am aware that there is a somewhat heated discussion on the subject of gamma 1.0 editing, which is not what I am proposing here. My concern is complete retention of the data delivered by the scanner. My reasoning is:

* The scanner sensor has a 16bit resolution.
* I acknowledge the sense in outputing a higher gamma file when using 8 bits/channel in order to space the resultant resolution perceptually. However when performing such a transform on the full bit data all I see is an increase in spacing of the scanner resolution at the shadow end at the cost of lost information in the highlights. I.e. I see no gain. * The scans are archival – I might wish to use the data in a couple of decades, with display technologies that may be completely different from today (i.e. why gamma encode the data with a value that derives from today’s display technology).

I would be particularly interested to hear from people in the high gamma camp(!), since I would guess from the gamma 1.0 camp I am going to hear "Go for it". The only potential problem that I can see here is whether the application of a gamma 2.2 curve through Photoshop/icc profile is any less accurate than in the scanner itself. I acknowledge that there may be others I have missed….

Cheers,

Gary Whitehead.

N.B. I too fought with the colour management on the scanner, and gave up in near disgust. Wolf Faust’s targets, and resultant ICC profiles gave the best results I had seen within minutes of generating them!