Portrettet i motlyset er skarpt.

Because portrettet is the definite singular form of the noun portrett.

• et portrett = a portrait
• portrettet = the portrait

Norwegian often adds the definite article as an ending on the noun instead of using a separate word like English the.

Since portrett is a neuter noun, its definite singular ending is -et.

For the same reason: motlyset is the definite form of motlys.

• motlys = backlight / backlighting / light coming from behind
• motlyset = the backlight / the backlighting

In this sentence, Norwegian uses the definite form in the prepositional phrase i motlyset, which can be understood as in the backlight or against the light depending on context.

It is a prepositional phrase modifying portrettet.

So the structure is:

• Portrettet = the portrait
• i motlyset = in the backlight / in backlighting
• er skarpt = is sharp

This means i motlyset tells you which portrait or under what visual conditions we are talking about. In this sentence, it most naturally attaches to portrettet: the portrait in the backlight.

Because skarpt agrees with the noun portrettet, which is singular neuter.

The adjective skarp changes like this in predicate position:

• common gender singular: skarp
• neuter singular: skarpt
• plural / definite adjective use in many attributive contexts: skarpe

So:

• Boken er skarp would sound odd semantically, but grammatically it shows common gender agreement.
• Bildet er skarpt = the picture is sharp

Since portrettet is a neuter noun, the correct form is skarpt.

Because this adjective is a predicate adjective, not an adjective placed directly before the noun.

In Norwegian, predicate adjectives usually agree in gender and number, but not in definiteness the same way attributive adjectives do.

Compare:

• et skarpt portrett = a sharp portrait
• det skarpe portrettet = the sharp portrait
  Here skarpe is an attributive adjective before the noun, so definiteness matters.
• Portrettet er skarpt = the portrait is sharp
  Here skarpt is a predicate after er, so it just agrees with the noun as neuter singular.

That is why skarpt is correct here.

Yes. Norwegian very often forms nouns by combining words into one compound.

Here:

• mot = against
• lys = light
• motlys = backlight / light from the opposite direction

This is very typical of Norwegian. English sometimes writes similar ideas as separate words, but Norwegian commonly prefers one compound word.

The basic order is:

Subject + verb + complement

But the subject itself is a longer noun phrase:

• Portrettet i motlyset = subject
• er = verb
• skarpt = subject complement

So the full structure is:

• [Portrettet i motlyset] [er] [skarpt]

This is a very normal Norwegian sentence pattern.

Yes, that can also work, but the emphasis changes slightly.

• Portrettet i motlyset er skarpt makes i motlyset feel closely tied to portrettet: the portrait in the backlight
• Portrettet er skarpt i motlyset makes i motlyset sound more like a condition under which it is sharp: the portrait is sharp in backlight

Both are possible, but they are not always identical in nuance. The original version makes the prepositional phrase feel more noun-related.

Because Norwegian usually expresses definiteness by adding it to the end of the noun.

So instead of:

• the portrait
• the backlight

Norwegian normally has:

• portrettet
• motlyset

This is one of the biggest differences from English. Norwegian can also use a separate determiner like det, but usually that happens in structures such as:

• det skarpe portrettet = the sharp portrait

There, both the determiner and the noun ending appear together because of the adjective.

It can absolutely describe image quality too. In this sentence, skarpt means something like:

• sharp
• clear
• in focus

This is very natural when talking about photos, portraits, lenses, or visual detail.

So here skarpt is not about something being dangerous or having a blade. It is about visual clarity.

A natural indefinite version would be:

Et portrett i motlys er skarpt.

That means A portrait in backlight is sharp, though depending on context it may sound a little unusual or generic.

Notice the differences:

• et portrett = a portrait
• i motlys or i motlyset depending on the exact intended meaning
• skarpt stays neuter because portrett is neuter

So the adjective agreement does not change just because the noun becomes indefinite; it is still neuter singular, so you still use skarpt.