Yellow is made up of light in the 500-700nm range.
Depending on the orange, it contains less energy than yellow in the 500-600 range, but similar energy in the other bands.
A yellow (#8) filter simply blocks light below 500nm. Neither Yellow or Orange have much energy in this range anyway, so it has little effect on either.
To distinguish yellow from orange, you could either use an orange (#21, or maybe a deep yellow) filter, which blocks below 550 (darkens the yellow, has less effect on the orange), or more extremely a green (passes 500-600) which will signifigantly darken the orange, but let more of the yellow through.
If you want to run the simulations for yourself, and have access to a Mac, then you can download my app from www.dctsystems.co.uk.
Last edited by 127; 11-22-2004 at 10:49 AM. Click to view previous post history.
Reason: typos - meant orange, not red!