Why didn’t the lookout see the iceberg?

It was clear, moonless night and the seas were calm with no winds. The temperature was absolutely freezing. You would probably be thinking, wouldn't it be easier to see an iceberg since there are no waves and the water was so calm? Actually it was the total opposite, because there was no wind and it was so calm, there were no swells to break over the iceberg. In addition, the low temperature made it even more difficult as any binoculars that were used would've been fogged up. (There were no binoculars used)

In addition, the iceberg that hit the Titanic could have been a black iceberg. (evidence by passengers who survived) Black icebergs are rather impure thanks to the soil and rocks within the glacier they break off from. This impurity allows sea water to fill their crevices, turning the iceberg a dark grey color until it empties out so the iceberg returns to it's normal white. This makes it difficult to spot even during the day, and near impossible at night.