![](/images/new-backgrounds/1319342/31934291x1.webp)
Figure A-7 Low Linear Region Response Curve
A generalized model for the display response curve accommodating the addition of a linear section as shown above thus requires the specification of four parameters in addition to the “gamma” exponent value:
For input values (I) ≤ A0:
Y = I/A1
For input values (I) > A0′
Y = [(I + A2)/(1 + A3)]γ
The response of the LP2480zx is automatically set to the correct standard as part of the color-space selection, using either the on-screen display (OSD) or using the HP Display Assistant software, or using the optional HP/X-Rite color calibration tools. Independently programming a custom response (as in the case of the user-defined custom color space preset) requires use of the HP/X-Rite calibration tools. Using the software provided with this calibration product, the display response may be programmed using the four-value-plus-gamma model described above.
Several of the standard color space specifications supported by the LP2480zx require the use of the “four-value” model, as they include a linear section in the response curve as described above. Of course, even the simple “gamma-only” model may be accommodated within the four-value model, by setting the A0, A2, and A3 parameters to zero, and A1 to a value of 1.0. The values used to describe the response
for the standard color spaces or output device specifications supported by the LP2480zx are listed in the table below.
Table A-3 Response Curve Constants for Various Color Spaces
Color space | A0 | A1 | A2 | A3 | gamma (γ) |
sRGB | 0.04045 | 12.92 | 0.055 | 0.055 | 2.4 |
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0.081 | 4.50 | 0.099 | 0.099 | 2.22222 | |
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| 0.081 | 4.50 | 0.099 | 0.099 | 2.22222 |
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Adobe® RGB | 0 | 1 | 0 | 0 | 2.19922 |
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0 | 1 | 0 | 0 | 2.6 | |
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40 Appendix A Advanced Color Management Features and Usage