How to change the gamma setting in Eprime?

[David McFarlane]

Regina,

Weighing in here...  Indeed, I do not think that 
E-Prime has any facility for handling gamma 
settings, but if you really want to know then you 
should submit your question to PST at 
http://support.pstnet.com/e%2Dprime/support/login.asp 
(and then post back here with their response).

If the issue is one of EP overriding gamma 
settings done externally (thanks for that 
insight, Mich), if you use EP2 then you might try 
setting the EP Display device to "Match desktop 
resolution at runtime", just in case that 
preserves externally done video settings.

Ultimately, if you want or need your program to 
handle gamma settings, then abandon 
E-Prime.  MATLAB using the Image Processing 
Toolbox and the Psychophysics Toolbox will handle this nicely.

-- David McFarlane, Professional Faultfinder


At 10/6/2011 05:02 AM Thursday, Michiel Spape wrote:
>Hi,
>I think Gamma settings are part of the video 
>card's driver specific settings - i.e., not 
>windows OS settings as such. I understand what 
>you set there gets reverted in E-prime once 
>running an experiment? If you want to avoid 
>that, you might delve deeper into the gfx card 
>driver settings to make sure the application 
>specific settings get overridden (a common 
>setting in ATI and NVidia cards) by your 
>driver's. Possibly, but doubtfully, your 
>settings remain somewhat more stable if you make 
>sure that the number of colours (i.e. in bits, 
>like 32) is the same in E-Prime as it is in the 
>OS (NOT true by default - 16 in E-Prime, 32/24, 
>generally in Windows), as well as the resolution 
>(and I know few people running their os in 
>640x480 as well). Moreover, if you'll look on 
>the internet, you're most likely to find 
>alternative drivers for your video card which 
>complement your existing options, possibly changing gamma and such.
>
>However, as a side point, I think you might want 
>to change the stimulus material rather than 
>changing the gamma, which inevitably compromises 
>quality of your stimulus material (which sounds 
>like something psychophysicists would deeply 
>care about). Use photoshop or whatever to change 
>gamma there, so you know exactly what is 
>happening, save that (this can be done in batch 
>processing, I heard, so it's not all that much 
>work), and only then use these files in E-Prime. 
>I don't know the exact situation here, but 
>generally, this is the better way to go.
>
>Best,
>Mich
>
>Michiel Spapé
>Research Fellow
>Perception & Action group
>University of Nottingham
>School of Psychology
>www.cognitology.eu
>
>
>-----Original Message-----
>From: e-prime at googlegroups.com 
>[mailto:e-prime at googlegroups.com] On Behalf Of Regina L
>Sent: 05 October 2011 23:14
>To: E-Prime
>Subject: How to change the gamma setting in Eprime?
>
>Dear all,
>
>I am trying to figure out how to change the gamma setting in Eprime as
>to have a linear luminance profile for my experiment, but I cannot
>find anything in the help files about this (nor on the display
>settings in Eprime). Has anyone done this before? I found an
>unanswered post regarding the exact same topic in the PST user forum
>(below).
>
>Thanks!
>
>Regina
>
>
>
>"Hi,
>
>We are trying to run an eprime object recognition study and we can
>change the gamma on the control panel of the computer but this setting
>does not remain when we execute eprime.  Is there any way to keep the
>gamma setting from the control panel in eprime?
>
>Alternatively, is there any way to control the color look-up table in
>eprime?  In the end we're trying to achieve a linear luminance profile
>as we do with our psychophysical experiments.
>
>Thanks,
>
>Vanessa"

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