For boundary questions, identify every subject-verb unit before choosing punctuation. A unit beginning with a subordinating word such as “although” may still contain a main clause and function as a complete sentence unit. Then check that supplementary words such as “respectively” remain attached to the clause whose information they clarify.
Hints
- Hint 1
Find the first clause
Determine whether the material describing what the photographer exposed can stand as a complete sentence.
- Hint 2
Keep reading after “although”
A sentence unit that begins with a dependent clause can still be complete if it later contains a main clause.
- Hint 3
Place “respectively” carefully
Consider which list correspondence this word explains and therefore which clause it should remain part of.
Step-by-step
- Step 1
Identify the first sentence unit
The text through “filters, respectively” is an independent clause: its subject is “Louis Ducos du Hauron,” and its verb is “exposed.” The word “respectively” connects the three negatives with the three filters and therefore belongs to this clause.
- Step 2
Analyze the remaining text
Although “although each negative recorded only a portion of the visible spectrum” is dependent, it is followed by the main clause “combining the three yielded a full-color image.” Together, these parts form a complete sentence unit.
- Step 3
Punctuate the boundary
A semicolon can separate the two complete sentence units. A comma before “respectively” correctly sets off that supplementary word at the end of the first clause.