Fade in effect when presenting visual stimuli

I am conducting an experiment in which visual stimuli (colored squares) are randomly presented to participants. I built these stimuli using Paint Brush for Windows and the colors are red, yellow, and blue. When I ask SuperLab to present these stimuli in the experiment, there is a sort of fade in effect which I cannot change (i.e., the color intensity of these stimuli become increasingly higher throughout its presentation). I wonder if that has happened with anyone else here and if there is a way of avoiding this. I need SuperLab to present these stimuli in a way that they look static and not as if they were lighting.

I would really appreciate if anyone could help with this.


Is there anyway you can post your experiment so I can see this behavior? Please post as an Experiment Package, which is found under the File menu within SuperLab.


Here is the Experiment Package and also the visual stimuli used in the experiment (separate file) so you can see this behavior.


Dia1_pre_rand_v2.zip (39.8 KB)

Quadrados coloridos com marcacج§aجƒo.zip (47.2 KB)

Thank you. I have another question, are you running your experiment on Mac, Windows or both?

Hi Monika,

I have been running the experiment exclusively on Windows. I have sent you the file from a Mac because sometimes I edit features of the experiment at home (where I use a Mac).

We have not been able to duplicate your issue on either a Mac or Windows computer. If you are on a laptop check your power saving set-up. Also, see if you have the automatic brightness adjustment enabled.

Hi, Monika,

We haven´t been able to find what is wrong either. We have checked monitor adjustments, but we found nothing that could account for the issue, so we decided to change monitors. Now it is working better. Thanks for helping us.