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I have never heard of Output Levels control in Powerpoint and can find no reference to it in the Help file.  Where does this control reside?  Thanks- Dave

On Jan 10, 2011, at 7:14 AM, Martin Spitaler wrote:

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> 
> Dear Amol,
> 
> you will rarely be able to affect the projector used for your presentation
> or plug your own in, so you better adjust the images accordingly. There are
> some simple but bullet-proof solutions to the problem. 
> 
> First, projectors and colour profiles are produced for hollywood movies,
> not scientific presentations, so the internal colour profiles are sigmoid,
> not linear, to give 'vibrant colours', but this eliminates the fine, dim
> structures typically essential for microscopy results. Also don't forget
> that not only our eyes will always be more sensitive to green than red and
> blue, but 10% of men can't distinguish red and green anyway. So convert your
> images to greyscale, that helps massively - only use colour images for
> overlays to show relative localisations. Best use black on white (i.e. black
> structures on a white background - inverting the fluorescent images), that
> also solves the problem with the room illumination (and people falling
> asleep in lunch time seminars).
> 
> You also need to be aware that projectors never use the extremes of the
> 8-bit depth, values close to '0' or '255' won't be visible (usually at least
> 20-30 values either side). That's why Photoshop offers the OUTPUT LEVELS
> adjustment, use it to 'shrink' the histogram to the range supported by the
> projector and room illumination (or use reduce it by ~30 either side, if
> unknown).
> 
> One option is also intensity-independent pseudo-3D presentation (e.g. like
> the '2.5D' option in the Zeiss confocal software), which shows intensities
> as peak heights.
> 
> I hope this helps,
> 
> Martin
> 
> ######################################
> Martin Spitaler, PhD
> 
> FILM - Facility for Imaging by Light Microscopy
> - Facility Manager -
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Dr. David Knecht    
Department of Molecular and Cell Biology
Co-head Flow Cytometry and Confocal Microscopy Facility
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91 N. Eagleville Rd.
University of Connecticut
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860-486-4331 (fax)