Gamma calibration with Minolta CS150

Builder
1

Hi there.
I want to do gamma calibration and only have a Minolta CS 150 photometer at hand. In the monitor center there is no CS150 but only CS100A. I tried scanning for my photometer(connected to the PC with USB cables, COM3) with the CS100A option but the runner said: Couldn’t initialize photometer CS100A: ‘utf-8’ codec can’t decode byte 0xe9 in position 28: invalid continuation byte.
Is there a way to do the gamma calibration with Minolta CS 150 or must I use one of the photometers in the options? :frowning:
Thanks very much if anyone could help!

OS : Win10
PsychoPy version : 2022.2.4
Standard Standalone? (y/n) :yes

2

Hi There,

I’ll share a few helpful resources. First here is a quick guide on how to “perceptually” gamma calibrate your monitor in PyschoPy (not as good as photometer, but I found interesting and helpful in understanding how to achieve the process in other ways!).

Even if your photometer isn’t automatically supported, if you can get luminance measures at a range of gamma values then this should be enough to calculate gamma and correct it. Are you able to obtain luminance measurements from your monitor? If so you could

  1. Present a window on PsychoPy at a range of gamma values.
  2. Plot the curve to get gamma (as below)
  3. Measure again to check luminance is linear

It isn’t as out of box for sure, but it does mean you can achieve gamma correction with the kit you have! By looking at the Coder View > Gamma Motion Null that can guide how to set gamma of the window win.gamma = [thisGamma, thisGamma, thisGamma]

|316px;x231px;

Becca

3

Hi there, Becca

Thanks for your advice, which helps a lot.

I happened to find that I could calibrate it with my photometer running gamma calibration in semi-auto mode.
The reason I didn’t know it at the beginning is that when there was supposed to be a window popping up for collecting measurements at the end, some errors appeared, resulting in no way of entering the luminance values. But I’ve found the solutions to this.

Anyway, thanks for all the resources you provided. They really bring me more ways to work around this problem. :smile: