Analysis of "harsh lighting."

[Alex Brown]

Dennis 

Many thanks for that - most enlightening!

- Alex.

> -----Original Message-----
> From: sc34wg6-bounces at vse.cz [mailto:sc34wg6-bounces at vse.cz] On
> Behalf Of Dennis E. Hamilton
> Sent: 25 March 2010 15:40
> To: 'SC 34/WG 6 mailing list'
> Subject: Analysis of "harsh lighting."
> 
> In researching Defect Report item SC34 N1309:03 on ODF 1.2 section 9.5.2 on
> "harsh lighting" I have the following results of that investigation:
> 
>  1. Harsh lighting is not a term of art for a special lighting mode in computer
> graphics mode.  The term is widely used in photography and it is discussed in
> the context of computer graphics, but only ODF 1.0 seems to have a harsh-
> lighting property for a light source.
> 
>  2. In photography and computer graphics, harsh lighting is understood as
> undiffused light from a point light source.  An example is the light from the
> mid-day sun on the Sahara Desert (or the open ocean or a mountain snow
> field) in a cloudless, clear sky.
> 
>  3. Most use of the term is around avoiding or devices for minimizing harsh
> lighting, not selecting it.  (Photoshop does not have a feature for harshening
> the lighting in an image.)  The same happens in theater and cinematography.
> (Sometimes a light is described as too hot, and this seems often related to
> harshness and intensity, not color temperature.)
> 
> APPLICATION IN ODF 1.0 AND PERHAPS OTHER DOCUMENT FORMATS
> 
>  4. In computer graphics applications that provide an illumination source
> other than ambient lighting and perhaps glowing (internally-lighted) surfaces,
> such as that to which draw:extrusion-first-(and-second)-light-harsh applies,
> THE LIGHTING IS HARSH BY DEFAULT.  IT IS WHAT YOU GET WITH SIMPLE RAY
> TRACING.
> (draw:extrusion-first-light-harsh is also true by default.)
> 
>  5. The reason that these OASIS discussions about Harsh Lighting are so high
> in Web searches on harsh lighting is that TURNING ON HARSH LIGHTING IS
> USUALLY NOT AN OPTION.  What 3D Computer graphics users want to be
> able to do is TURN IT OFF OR MITIGATE IT.  No one else does anything active
> to turn it on.  It's what you get without some sort of intervention.  Just like
> photographing someone standing in bright sunlight.
> 
>  6. These are, of course, my personal findings.  I have no idea what the
> drafters of ODF 1.0 had in mind for the behavior that draw:..-harsh="false"
> would elicit in contrast with the default harsh=true case, since there is
> apparently no simple true/false way to speak of light being "soft" or not-
> harsh.
> 
>  7. I have added a comment to the ODF TC JIRA issue OFFICE-2200 that tracks
> against the ODF TC disposition of SC34 N1309:03.  You can see our full issue-
> discussion record at <http://tools.oasis-open.org/issues/browse/OFFICE-
> 2200>.
> 
> Respectfully submitted,
> 
> 
> 
> 
> 
> 
> 
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