Colours
 

I'm sorry but I've got a really basic question. I am self studying and get that some colours have singular/plural whilst others have male/female/singular/plural but the books don't say why. It looks from the examples that it is as simple as those ending in 'o' have both forms with the ending changing to 'a' (negro, negra) but those ending in a different letter (verde) just have the two forms. Is it really that simple or do I have to learn every which form it is for every single colour, just like I learn gender for nouns?

Thanks

Sue

Never apologize for a basic question, unless it's a stupid one, and this one seems perfectly sensible. A colour can be a noun (with a specific gender, el azul) or an adjective (the blue dress). I assume you are asking about adjectives, and any colour is treated exactly as any other adjective. You need to look at the general rule about adjective agreement. But adjectives ending in -o change to -a to agree with something feminine:

el sol amarillo
la luna amarilla

Adjectives with other endings do not change for m/f singular, but might change in the plural, for example blue azul (masc. or feminine singular) and azules (m/f plural).

So you need to learn colours as adjectives, and learn the different ways adjectives change according to their endings. It's actually quite easy.
Does that help?

If a colour is simple, it's probable people have been using it as an adjective during centuries. In that case there's always a difference between singular and plural, though not necessarily about gender. If a colour is "modern", "complex" or "subtle" then people speaking of them is a modern times phenomenon, it's probable used in a single way meaning that xxxx is used as "de color xxxx":

Casa de color rojo, casas de color rojo, autobús de color rojo, autobuses de color rojo ---> casa roja, casas rojas, autobús rojo, autobuses rojos

casa taupe, casas taupe, autobús taupe, autobuses taupe

Sometimes, the colour is not simple nor complex and people tend to vacillate about using singular-plural or using just the colour name (one of them is more common, but when lacking any information the latter is advisable):

casa rosa, casas rosas or casas rosa, autobús rosa, autobuses rosas or autobuses rosa

But when a colour has a complex name involving an simple colour qualified by an adjective, it's used in its singular form:

casa amarillo limón, casas amarillo limón, autobús amarillo limón, autobuses amarillo limón

So, following the examples above in red, pink, taupe or lemon yellow:

roja, rojas, rojo, rojos
azul, azules, azul, azules
amarilla, amarillas, amarillo, amarillos
verde, verdes, verde, verdes
blanca, blancas, blanco, blancos
negra, negras, negro, negros
gris, grises, gris, grises
marrón, marrones, marrón, marrones
dorada, doradas, dorado, dorados
plateada, plateadas, plateado, plateados
cobriza, cobrizas, cobrizo, cobrizos
rosa, rosa (rosas)
violeta, violetas (violeta)
turquesa, turquesa (turquesas)
celeste, celestes (celeste)
naranja, naranjas (naranja)
sepia, sepias (sepia)
fucsia, fucsias (fucsia) [or fuchsia/s]
bordó, bordós (bordó) [or bordeaux, or burdeos]

púrpura
borgoña
borravino
crema
índigo
almendra
arena
tango
caoba
ocre
siena
malva
cardenal
cemento
teja or terracota
caqui (or khaki)
beige
león
herrumbre
cian
palta
salmón
...

amarillo limón
verde nilo
verde espinaca
verde musgo
verde oliva
marrón africano
verde esmeralda
verde agua
verde inglés
rosa agua
azul eléctrico
azul de Prusia
azul Francia
azul de ultramar
azul cerúleo
rojo carmín
rojo escarlata
rojo bermellón
blanco tiza
blanco roto
azul cobalto
amarillo de cadmio
gris acero
...

Oh! I forgot to mention dark and light colours as well as colours with a tinge. They are dealt like the last group

verde claro
verde oscuro (or obscuro)
azul claro, etc.
amarillo verdoso
azul rojizo
marrón grisáceo
marrón amarillento
verde azulado
...

Gracias to you both - that does help a lot.

Sue