SMART III - Video Calibration Toolkit

Steve Smallcombe's SMARTAVTWEAKS site

Color Balance

Color balance and grayscale tracking are shown in several ways with SMART III. The Color Balance chart on the right shows color balance in terms of the ratio of all three colors as a function of IRE level. This example is from the Sanyo Z1 prior to SMART calibration. The picture in this state of calibration (or lack thereof) looked too red, except in dark scenes where the shadows seemed a bit blue. The Color Balance Chart is probably the most useful chart for understanding what is happening to your projector’s color balance at the various IRE levels.

From these RGB ratios, however it is possible to calculate many other metrics including xy chromaticity values and correlated color temperatures as shown below. These data for these particular charts were taken from a Sanyo Z1 spreadsheet at the beginning of calibration and does not represent the projector as ultimately tweaked.

The three charts or diagrams show here show the same information, but in different ways. The SMART color balance chart allows you do directly compare RGB ratios at all IRE levels relative to the reference level at 1. The xy chromaticity diagram shows this same information, but in this case, transformed into the CIE color space. The reference point is shown as the unfilled circle near the middle of the diagram and represents the ideal, D65.





The Color Temperature chart shows again the same information, but in this case, as a “Correlated Color Temperature” calculated from the above xy coordinates. Note that is Color temperature diagram is probably the least informative of the three, as the Correlated Color Temperature is particularly insensitive to green in the regions of color space where we will be operating. So you may find that during the calibration process, the Color Temperature may read very close to the desired 6500, but that the SMART Color indicates that green is either too high or to low. This is because 6500K does not describe a precise location in color space, (unlike D65) but in fact, a whole locus of lines that can have significant variation in the green magenta balance.

You may also want to read the page on SMART and absolute color balance.


Next you may want to read about SMART and Gamma Tracking.


Home Page

Introduction to how SMART works

Frequently Asked Questions about SMART

Here is what's new is SMART III version 1.2

The Dummies Guide explains the SMART process in a non-technical way

Buy SMART III at EnhancedHT - your exclusive source for all SMART products

Not sure you are ready to try SMART yourself? Have a certified SMART person do the calibration for you

Having trouble? Learn the most common mistakes people make using SMART

Read about using bias lights to improve perceived black levels.

Here are some additional tips for the SONY projectors and solution to common problems.







Copyright 2001-2005 Steve Smallcombe