> On 1/27/2011 11:47 AM, Alain wrote:
>> A factor of only 255 seems like very small, given that you can easily
>> find HDR images with a range of 50 000:1 and more.
>> If the Sun does show in the image and you have dark details in deep
>> shadows, the range can easily shoot past 1 million to 1.
>
> So, what would be a safe value to use? I heard that HDR images support
> 32 bits for each color channel. So a value of 4,294,967,295 would work,
> right?
>
> Sam

Maybe yes, maybe no.
It all depends on the actual range of the image you use and what amount 
of precision loss you are willing to accept.

If the image have some extremely bright areas and you are not to 
concerned about loosing precision from the darkest regions, dividing by 
1000000 can be correct/acceptable. In this case, you may even need to do 
some clipping.

If your actual range is smaller, with some subtile darker details, then 
your 255, or less, can be enough.

If your high range is from a night scene where everything is dark, it 
could be an idea to actualy multiply your values...



Alain

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