On 09/13/2016 01:00 PM, clipka wrote:
> Am 13.09.2016 um 18:39 schrieb William F Pokorny:
>
>> When the plane's pigment is set to color rgbft <1,1,1,1,1> and the
>> background is set to anything but black, an odd inverted shadow shows up
>> on the transparent plane. Could be used for special effects I guess.
>
> Yes, setting colours to any value with finish+transmit>1 may cause quite
> unexpected effects. Most notably, the effective opaque component of any
> pigment is (rgb)*(1-finish-transmit), so with finish+transmit>1 you get
> an effective opaque component that is /negative/.
>
>> Does make me wonder if "color 1" should be promoted as it apparently is
>> in the posted code?
>
> Presuming that 3.7 reacts in the same manner, I'd say it should trigger
> a warning.
>
I checked and it does behave in the same way in 3.7.

I almost always specify the full rgbft or srgbft qualifier and values to 
not get tangled up.

I got lazy here - and I had it in my head that "color 1" promoted only 
to a 3 value vector. It indeed promotes to 5.

To be sure - we are adding the warning on the promotion of color 
specified as a single float value >0 getting promoted to a 5 value 
vector? If so, suppose this likely work at a skill level I could go 
after if you want?

Bill P.

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