Color Temperature Orange (alternatively, Correct to Orange). A range of color correction filters used to lower a source's color temperature. Available from all four major gel manufacturers and also available in dichroic filters.
Full CTO will convert 5500K to 2900K
1/2 CTO will convert 5500K to 3800K
1/4 CTO will convert 5500K to 4500K
1/8 CTO will convert 5500K to 4900K
Some also offer 1/3, 2/3, and 3/4 varieties.
For more information, see Color Correction Charts by Mike Callahan.pdf.zip. Note that not all manufacturer's products are exactly equivalent.
Full CTO will convert 5500K to 2900K
1/2 CTO will convert 5500K to 3800K
1/4 CTO will convert 5500K to 4500K
1/8 CTO will convert 5500K to 4900K
Some also offer 1/3, 2/3, and 3/4 varieties.
For more information, see Color Correction Charts by Mike Callahan.pdf.zip. Note that not all manufacturer's products are exactly equivalent.