I understand that printing multicontrast paper with a cold light head may require a Wratten CC40Y filter (in addition to the contrast filter). I happen to have laying around here a set of Cibachrome filters, including a 40Y. Are they the same? Given that the "40" is intensity and the "Y" is color, I would think so. They are at least roughly the same color (judging by screen shots of the Wratten filter).