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use_uv: (optional) Species whether CIE xy or CIE u’v’ values are provided for the primaries and white point.

This attribute accepts the values “xy” or “uv”. If this optional attribute is omitted from the tag, xy values are

assumed.

external: This attribute is used in conjunction with the “external_primaries” tag to allow the use of

nonsupported measurement instruments. Used as a ag, this attribute supports values of “TRUE” and

“FALSE”. It should be set to FALSE unless an external_primaries tag is also included in the StudioCal XML le.

Use of this tag is discussed later in this user guide.

Gamma

This tag allows you to specify the gamma or EOTF to use for your color space preset. The tag contains one

attribute and is structured as follows:

The value attribute supports the following values:

1.0–3.0: Power function gamma values. Typical values are 2.2, 2.4, and 2.6.

sRGB: Generates an sRGB EOTF per the sRGB standard. This EOTF curve is roughly equivalent to a 2.2 gamma

with a linear segment in the lower region.

BT1886: Generates an ITU-R BT.1886 EOTF. This EOTF is designed to more closely represent the desired

response for video production and is typically used with the BT.709 and BT.2020 color primaries.

EPD: Generates an Equal Probability of Detection EOTF, as specied in the Society for Information Display

Information Display Measurement Standard document. This grayscale function is designed for use when

viewing satellite imagery and is intended to make dimmer low-contrast objects of interest more easily

readable when residing near brighter areas in the image.

Core calibration tag examples

The following are examples of a StudioCal XML le showing the usage of the core calibration tags. The rst

example instructs the display to calibrate one preset with BT.709 primaries, a D65 white point, and a BT.1886

gamma. It stores the calibration in the user memory location.

<?xml version="1.0" encoding="ISO-8859-1"?>

<calibration_info>

<target_primaries rx="0.640" ry="0.330" gx="0.300" gy="0.600"

bx="0.150" by="0.060" wx="0.3127" wy="0.329" wY="80"

external="FALSE"/>

</calibration_info>

</calibration>

</studiocal>

74 Chapter 4 Using the StudioCal XML schema