Opposite colors for my stimuli

[Michael]

Firstly:

Please surround python code with backticks

When you include python code on this forum please put triple “backticks” like this ``` on the line before and the line after your code. If you’ve done it correctly then your code will appear in a grey box with correct indentation like this (check the preview of your post on the right hand side before posting it) and other people will be better able to work out what might be right/wrong with your code. if myVal==True: break If you’ve already posted something that didn’t follow this rule th…

We can’t easily cut and paste your code if it isn’t formatted as code (e.g. straight quotes become curly quotes).

Secondly:
I’m not really sure what the issue is here. Perhaps things will be clearer if you change the spatial frequency to be 0.03 rather than 3:

What is the default size of GratingStim in pixels? Grating goes crazy when unit was set to pix

See this page by @djmannion where he describes how to set the spatial frequency if the stimulus has dimensions defined in pixels: http://www.djmannion.net/psych_programming/vision/draw_gratings/draw_gratings.html#spatial-frequency and an old post from @jon here: https://groups.google.com/d/msg/psychopy-users/KrMtf6fWZu0/Vl6EI3MN9OMJ