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Adopted testing conditions.

1. Display mean luminance: 30 cd/m^2 +-5 (this is easily achieved by normal monitors)

2. Display frame rate: a *minimum* of 60 Hz.

3. Display pixel size: 0.5 min with image size of 256 pixels square.
(for low frequency stimuli pixel replication may be necessary to achieve gray scale resolution. In those cases effective pixel size will be 1 min.)

4. Display gray scale resolution: 1/4 or less of the stimulus threshold (d'=1). Stimuli will be oriented horizontally to avoid adjacent pixel interaction effects.

5. Stimulus pixel replication: Used when needed to achieve gray scale resolution and avoid adjacent pixel interaction effects.

6. Stimulus temporal waveform: 500 msec Gaussian (125 msec sd)

7. Number of stimuli: 45.

8. Binocular viewing.

9. Natural pupils.

10. Presentation: 2AFC or rating scale (not two alternative spatial FC - screen size limitations)

11. Data collection/analysis: Use any objective data collection method. (adaptive staircase, Quest, method of constant stimuli...) The majority of trials must be located near the final threshold (d' = 1-2) to avoid erros based on assumptions about the slope of the psychometric function.

12. Trials/error bars: With the methods flexibility described above (11) we adopted maximum acceptable standard error bars of 25% the reported threshold for individual run. Final threshold based on a minimum of 4 runs with stimulus presentation order blocked to avoid order effects.

13. Threshold reporting: 84% correct on 2AFC.

14. Fixation: Thin high contrast one pixel wide "L" shaped pattern located at the stimulus boundary that is not extinguished during the trial.