2011

Working with 1D LUTs
A 1D LUT is generated from one measure of gamma (white, gray, and black)
or a series of measures for each color channel. You typically work with a pair
of 1D LUTs: the first converts logarithmic data to linear data, and the second
converts the linear data back to logarithmic data to print to film.
1D LUTs can be used as import and export LUTs, and as monitor LUTs. Import
and export LUTs are mainly used to convert between the logarithmic data
contained in film scans and the linear data used within the application.
Monitor LUTs ensure the image displayed on the monitor resembles the final
output without the actual image data being modified.
You can apply a 1D LUT when importing a film clip, and then convert the
image data back to logarithmic data when exporting the final output. For
example, you can use a 1D LUT on import to convert 10-bit to 8-bit, 16-bit,
32-bit, or linear images for manipulation. Typically, you would then apply
the inverse LUT on export to restore the logarithmic data, ensuring that the
modified film print exactly matches the original shot.
NOTE You can use 1D LUTs created outside the environment. However, to be
recognized, the 1D or 3D LUT file must be in the correct format and be named
correctly. Comment lines are permitted.
Using 1D LUTs Created Using Third Party Software
You can use 1D LUTs created in other applications as long as they are in the
recognized format. All 1D LUT files must have the .lut extension. You should
save all 1D LUTs in the project's LUT folder for ease of use, and so they can
be archived with the setups of the project.
The 1D LUT Format
The 1D LUT file begins with a declaration of the number of tables and the
number of entries per table:
LUT: <number of tables> <number of entries per table>
The number of tables in the file depends on the channel resolution required.
For a LUT in which all three RGB channels are converted using the same
values, just one table is required. To convert the three channels using different
values, use three tables. For three channels plus alpha, use four tables. The
number of entries in each table corresponds to the bit depth of the source file:
256 entries for 8-bit resolution, 1024 for 10-bit and 4096 for 12-bit. For
example, a LUT operating on three 8-bit channels independently would have
the following declaration:
Working with 1D LUTs | 619