why start with a painful bright white screen?

1
i have been using psychtoolbox with matlab6.5 for years. i wanted to
look into the new one (with matlab7.3 as it dosen't even work with 7.4
yet) but i just found out it starts up with a painful bright white screen.

any researcher with any experence at all would realize this has a
major effect for several minutes.
http://webvision.med.utah.edu/light_dark.html

even if i try to start up in black:

>> [windowPtr,rect]=Screen('OpenWindow',1 ,[0 0 0 ]);

it takes 4-10 seconds to turn black.
here's one example:
>> tic
>> [windowPtr,rect]=Screen('OpenWindow',1 ,[0 0 0 ]);
>> screen('closeall');
>> toc
>>
>> Elapsed time is 7.048752 seconds.

and here it turned black at the same instant as closing.

i just updated my radeon 9800 pro driver and have 2 screens. what else
would delay the startup process?
if i can't i fix this, the entire platform is useless.
2
On 27.06.2007, at 21:10, bcoe wrote:

> [...for full reference, see below ...] if i can't i fix this, the
> entire platform is useless.

not quite: You can turn off the white screen by changing the
'VisualDebugLevel', see http://psychtoolbox.org/wikka.php?
wakka=FaqWarningPrefs . Don't know whether this works on a dual
display setup, though.

oldVDLevel = Screen('Preference', 'VisualDebugLevel', 1);
tic
[windowPtr,rect]=Screen('OpenWindow',0 ,[0 0 0 ]);
screen('closeall');
toc
Screen('Preference', 'VisualDebugLevel', oldVDLevel );

best, jl

On 27.06.2007, at 21:10, bcoe wrote:

>
> i have been using psychtoolbox with matlab6.5 for years. i wanted to
> look into the new one (with matlab7.3 as it dosen't even work with 7.4
> yet) but i just found out it starts up with a painful bright white
> screen.
>
> any researcher with any experence at all would realize this has a
> major effect for several minutes.
> http://webvision.med.utah.edu/light_dark.html
>
> even if i try to start up in black:
>
>>> [windowPtr,rect]=Screen('OpenWindow',1 ,[0 0 0 ]);
>
> it takes 4-10 seconds to turn black.
> here's one example:
>>> tic
>>> [windowPtr,rect]=Screen('OpenWindow',1 ,[0 0 0 ]);
>>> screen('closeall');
>>> toc
>>>
>>> Elapsed time is 7.048752 seconds.
>
> and here it turned black at the same instant as closing.
>
> i just updated my radeon 9800 pro driver and have 2 screens. what else
> would delay the startup process?
> if i can't i fix this, the entire platform is useless.
>
>