Oops, my apologies. I' m tech challenged( took several attempts just to do the post) so didn't even consider that the color subtleties wouldn't be visible. I'm mixing Pantone colors.Thanks for the feedback.
I'm not saying that the subtilties aren't visible, just that they're subtle. You should look with a browser and see if you see in the RGB files what you saw in Ps (are you using Ps?) when you made the images. If you are, then probably your audience is.
If you're using Ps, you can convert your tritone file to an sRGB one for web distribution. I'm assuming that's what you did. It's been so long since I did it that I can't remember the details. Are you using one Pantone color per ink, and creating your own tone curves for each ink?
I have found that there is often a great deal of difference between Ps and Id simulations of any spot color and the real thing (and the inks in tritones can be thought of as spot colors if you're trying to distinguish them from the standard process colors, although they are used as process colors in tritones), perhaps due to dot gain on the press, perhaps to other things.
Jim