Counting adjectives

Can you please check if the following shortened forms are correct?

1. Rich people - the rich OK
2. Five rich people - five riches Not OK
3. Blue Play Doh - the blue You can only say this if the context has already clearly established that you are talking about portions of Play-Doh

1. Correct.
2. No.
3. Possible in the right context. May not always be the most natural.
4. Barely possible.

Thank you.

Then you two have a different opinion about #4?

Is there any examples that say two blues or something like that?

onizoThank you. Then you two have a different opinion about #4? Is there any examples that say two blues or something like that?

I hadn't seen Clive's reply when I wrote mine, but it may be that we are interpreting "pieces" differently. I was thinking of amorphous lumps of "stuff" that had been pulled out of a tub. "five blues" seems a bit more feasible to me

Thank you.

How about the following?
1. A piece of blue Doh in a ball shape - a blue.

Can a blue piece of Play- Doh be shortened to "a blue"?

onizoThank you.How about the following? 1. A piece of blue Doh in a ball shape - a blue.Can a blue piece of Play- Doh be shortened to "a blue"?

I would say usually not. It would only be in a situation where you had to repeatedly refer to different coloured *****. Then you might eventually start to say "a blue", "a red" etc. rather than "a blue ball", "a red ba

Thank you GPY.