Orange, in J.R.R. Tolkien's words

The Quenya word for orange (the fruit) is culuma. The Quenya word for orange (the color) is culuina.

I didn't find a Sindarin word for orange.

Brown, In J.R.R. Tolkien's words

The Quenya words for the color brown is varnë.

The Sindarin words for the color brown are baran and rhosg or rhosc.

Gray, in J.R.R. Tolkien's words

The Quenya words for the color gray (or grey) are sindë and sinda.

The Sindarin words for the color gray (or grey) are mithren and thind.

Blue, in J.R.R. Tolkien's words

The Quenya word for the color blue is luin or lúnë. Pale blue is helwa.

The Sindarin word for the color blue is luin or lhûn. Pale blue is elu or elw.

Green, in J.R.R. Tolkien's words

The Quenya word for the color green is laica or laiqua (earlier sources). Another word for green is wenya (yellow-green, fresh)

The Sindarin word for the color green is calen.

Yellow, in J.R.R. Tolkien's words

The Quenya word for the color yellow is malina. Golden is laurëa or laurina.

The Sindarin word for the color yellow is malen.

Red, in J.R.R. Tolkien's words

The Quenya words for the color red are carnë (red), aira (red, copper-coloured) and narwa (fiery red).

The Sindarin words for the color red are caran (red) and ruin (fiery red).

Black, in J.R.R. Tolkien's words

The Quenya words for the color black are morë, and morna (dark, gloomy, blackness) or morqua (a non-LOTR form of morna).

The Sindarin word for the color black is morn.

White, in J.R.R. Tolkien's words

Some Quenya words for white are fána (white, cloud), lossë (snow-white), and ninquë (white, chill, palid).

Some Sindarin words for white are fain (white, cloud), gloss (snow white, dazzling white), and nimp (pale, white).