This document outlines as much of the Scitex CT (CH) file format as I have been able to reverse engineer. It works for all the files I have tried it on, but you probably have different files than I have.
The scitex ct file format is a common file format used in the prepress industry. Ct files will almost always will contain either a CMYK or a greyscale image.
Common extentions are .ch .ct and .sct
I think that ct stands for "continuous tone"
NOTE: All numbers are stored in the big endian byte order
| Offset | Length | Description |
| 0x0 | 0x50 | Comment string padded with spaces |
| 0x50 | 2 | Text "CT" |
| 0x400 | 1 | Units (0=MM,1=INCH) |
| 0x401 | 1 | Number of Channels |
| 0x402 | 2 | Format (7=RGB, 8=GREYSCALE, 0xF=CMYK) |
| 0x404 | 14 | Height in Units stored as a Scitex FP |
| 0x412 | 14 | Width in Units stored as a Scitex FP |
| 0x420 | 12 | Height in pixels. Stored as 12 digits of text including sign ("%+012d"). |
| 0x42C | 12 | Width in pixels. Stored as 12 digits of text including sign ("%+012d"). |
| 0x800 | W*H*C | Image Pixels stored in row interleaved format. |
+.<number (8 digits)>e<sign><exponent (2 digits)>
Channels: 3
Color Space: RGB
Size (mm)
Width: 37.499997
Height: 24.999998
Size (pixels)
Width: 150
Height: 100
Resolution (pixels/mm)
Width: 4.00000032000003
Height: 4.00000032000003
If you have any information on the scitex lw (linework), nct (new ct), or nlw (new lw) file formats, please pass it along
If you have any questions or comments about this document email me at jaycox@electricmessiah.org