A value from 0 ot 255 specifying the intensity of the red component of the screen color.
Higher values mean the color has more red.
The following displays the value of screencolorred in a text stimulus:
<text sometext>
/ items= ("screencolorred = <% block.someblock.screencolorred %>")
</text>
The following displays the value of screencolorred in an instruction page:
<page somepage>
screencolorred = <% block.ablock.screencolorred %>
</page>