hmm, the orange filter doesnt seem to help bring up the contrast much for #01 and #03
from b+w site said:
This bright-orange filter darkens blue and violet as well as green and yellow-green. It is indispensable for all landscape and architectural photography which require vivid and clear contours. The sky is distinctly toned with the clouds clearly contrasted against it. This filter is popular for nude photography under natural light. Filter factor is approx. 4.