"Lighter" vs. "brighter"

Question

I'm trying to find information about the grammatical correctness of interchanging lighter and brighter in the sense of:

1. I turned on the lamp and the room became lighter.
2. I turned on the lamp and the room became brighter.

I think that 1 is wrong, but I can't find information backing that up. Could anyone explain why, especially as some dictionaries may list light and bright as synonyms (ex: Dictionary.com (def 24), citing Random House)?

[edit]

I think I can narrow my question sufficiently, especially per my comments below. I believe using the term lighter to refer to levels of light, such as in the first phrase, is incorrect as as lighter appears to mean paler, while brighter means more vivid, intense, or luminous; however the two meanings while similar, do not appear to overlap. I am try to get confirmation/refutation of this.

For example, brightness and lightness appear to refer to two separate, but somewhat related, properties of perception: brightness to radiance or luminosity, and lightness to value of tone. (Compare: bright red to light red)

Finally, and the primary basis of this question, is a reference from the OED:

a. Bright, shining, luminous. Of a fire: Burning brightly. Phrase, on (of, in) a light fire : in a blaze (very common in 16–18th c.). Obs.
["light, adj.2." OED Online. Oxford University Press, September 2014. Web. 30 October 2014.]

The key here being the "obsolete." The other two variants pertaining to the same topic - one an adjective and the other an adverb - are likewise obsolete.

For illustration, consider the two additional example sentences:

1. The lamp is too light.
2. The lamp is too bright.

Thus, I suppose, the question worded distinctly would be: Is the first sentence incorrect? If not[/so], is it colloquially and/or grammatically [in]correct?

Answer 1

"Light", as an adjective, can certainly mean having an abundance of light, i.e. not dark.

In your context, it is perfectly clear that you mean that turning on the lamp makes the room lighter. To that effect, the following is fine:

Having more windows, the kitchen was lighter than the living room.

Using the word "brighter" is more obvious without context because it doesn't carry the ambiguity of "lighter", that being that it can also mean "less heavy". Everyone knows that turning on a lamp doesn't reduce the weight of the room so, in your example, lighter works fine.

In summary, both are fine but if you think context is unclear then "brighter" would be more obvious.

Answer 2

Though sometimes they can be a little flexible, "light" here usually refers to a pale(r) colour. (It can also refer to weight, both real and felt/psychological)

"I wanted a lighter pigment, so I mixed in some more white."

(Added in edit:) "The lamp's bulb's colour in my room is too light. Do you have those golden or orange lightbulbs? I don't like white light[n] by my bed."

"I like the light cream for the walls. Anything too dark, like the ochre, will suck up all the light[n] from the lamps and windows."

We can also describe an area as "having good light[n]" (or lighting):

"This office always has good light, thanks to the south-facing skylight."

"The lighting in here is great; how many bulbs are set into this ceiling?"

By contrast, "bright" is usually use for a more vivid, but also more luminous-seeming colour (it stands out, and catches your eye) (a), or for an object which emits or reflects light (b)

a)

"The petal pink is nice for a light pink, but I want something bright. Don't you have fuschia, or hot pink?"

b)

"The lamps are/The room is much brighter now, with the new bulbs in."

"The moon is very bright tonight."

"She polished the platters until they shone mirror-bright."

Answer 3

It can be easily understood with the following examples 1. My bag is lighter than yours. 2. The moon was looking brighter at the full night.

Answer 4

Lighter is wrong because lighter refers to weight, whereas brighter refers to the amount of light. If you turned on the lamp and the room became lighter, you would be saying the room now weighs less than it did before.If you say the room became brighter, you would be saying that there is more light in the room then there was before

English is kinda confusing sometimes, because we use the same word in different contexts to mean different things:(.