Der blaue

Hello,

While doing lesson 2.3, I didn't notice the German adjective "blau" in upper case.
http://en.pons.com/translate?q=blau&l=deen&in=&lf=de

Now at lesson 5.3, I see that it may not be necessary to capitalize "blaue".
http://en.pons.com/translate?q=blaue&l=deen&in=&lf=de

Can anybody explain this situation?

Lower case adjective:  (Thank you Paul & Byron for your explanations below - Here blue describes suitcase, so it is a pure adjective)
Der blaue Koffer
The blue suitcase
5.3 Retail Therapy http://members.rocketlanguages.com/lessons/46

Upper case like a noun: (Here we turn blue into a noun, so it is capitalized in German)
Der Blaue ist mein Pullover
The blue sweater is mine
2.3 At The Airport http://members.rocketlanguages.com/lessons/34

Ja, der Blaue ist mein Koffer.
Yes, the blue suitcase is mine.
2.3 At The Airport http://members.rocketlanguages.com/lessons/34

Thank you,
Jason

(Update 2014-01-26) Thanks Byron. The best reference I have found is this one:
http://german.about.com/library/weekly/aa020919b.htm
I have to come back to this with somebody that knows the rules and see how it applies above.

3. ADJEKTIVE 1 (Adjectives 1)

German adjectives — including those of nationality — are NOT capitalized. In English, it is correct to write "the American writer" or "a German car." In German, adjectives are not capitalized, even if they refer to nationality: der amerikanische Präsident (the American president), ein deutsches Bier (a German beer). The only exception to this rule is when an adjective is part of a species name, a legal, geographic or historical term; an official title, certain holidays, or common expression: der Zweite Weltkrieg (the Second World War), der Nahe Osten (the Middle East), die Schwarze Witwe (the black widow [spider]), Regierender Bürgermeister ("ruling" mayor), der Weiße Hai (the great white shark), der Heilige Abend (Christmas Eve).

Even in book, film or organizational titles, adjectives are usually not capitalized: Die amerikanische Herausforderung (The American Challenge), Die weiße Rose (The White Rose), Amt für öffentlichen Verkehr (Office of Public Transportation). In fact, for book and movie titles in German, only the first word and any nouns are capitalized. (See the article on German Punctuation for more about book and film titles in German.)

Farben (colors) in German can be either nouns or adjectives. In certain prepositional phrases they are nouns: in Rot (in red), bei Grün (at green, i.e., when the light turns green). In most other situations, colors are adjectives: "das rote Haus," "Das Auto ist blau."

I think you are correct that in German blaue/Blaue can be used both as an adjective or a noun. We don't typically do that in English particularly for inanimate objects, but one exception I can think of is in reference to horses, e.g. palomino horse. Here palomino is an adjective referring to a type of horse. One could also say the palomino over there is my horse. Here palomino is used as a noun. Another example is hair, e.g. blond hair. Blond is an adjective in this usage. However, to say the blonde over there is my wife would be using it as a noun.

Hi there,

Byron you are right. For English speakers it might be hard to relate as it is harder in English to make adjectives to nouns. In der "Der Blaue ist mein Pullover", "Blaue" is a noun. The noun "Koffer" became redundant in the conversation. 

"Der Blonde ist kleiner." In English you would ad the word "guy", "person" or "man". "The blond guy is smaller."

Regards

Paul

Thank you both. I have updated my question to explain the solution.

The new forum doesn't show the dates. I really hate that. 3 weeks? 1 year?  Why bother including a date at all. It was much better before when it included all details "Paul-Weber - February 20, 2013, 8:17 pm".

Seems it would be more difficult to calculate the elapsed time and decide if it should be written in days, weeks, or years than it would be to just show the time. I'm so disappointed with these forum changes. Who would have requested that feature?

-Jason