+-+-+-+¢ "COLORBAR.OBJ" PROGRAM WILL BE FOUND¢ ON THIS Sept/Oct 1995 OL' HACKERS AUG¢ NEWSLETTER DISK!¢¢ WHAT IS IT?¢¢ COLORBAR.OBJ is a binary load file¢ which, when loaded, displays NTSC¢ Color Bars on a color TV or monitor¢ (or a grey scale on a Black and¢ White). This is very useful for¢ calibration of your set, so that if¢ you write programs which use color,¢ you know that the colors you choose¢ will be correct.¢¢ WHAT IS IT USED FOR?¢¢ These bars are used by broadcast¢ engineers to test the calibration on¢ video transmissions. To insure that¢ the bars which the Atari will generate¢ conform to the NTSC standard, they¢ were checked using a vector scope (for¢ the hue) and a waveform monitor (for¢ the luminance level).¢¢ IMPORTANT¢¢ -----------------------------------¢ ALL AUTOMATIC COLOR AND LEVEL CONT-¢ ROLS MUST BE OFF BEFORE YOU BEGIN¢ MAKING ADJUSTMENTS!!!!!!!!!!!!!!!¢ -----------------------------------¢¢ WHAT YOU SHOULD SEE!¢¢ The following is a description of¢ the correct color/luminance of each¢ bar:¢ 1. The first WHITE bar (far left) ¢ is should be 75% luminance and pure¢ WHITE. More about this (luminance¢ levels) later.¢ 2. The second bar should be YELLOW¢ in hue and have a luminance level of¢ approx. 65%.¢ 3. The third bar should appear CYAN¢ (which is a light aqua-marinish color)¢ with a luminance level of approx.¢ 55%.¢ 4. Bar #4 should look GREEN and have¢ a luminance level of 45%.¢ 5. The fifth bar is MAGENTA with a¢ luminance level of 35%.¢ 6. The sixth bar is a pure RED, with¢ a luminance level of 25%.¢ 7. The seventh bar (far right) is¢ pure BLUE and will have a luminance¢ level of about 15%.¢¢¢ PLUGE (WHATS THAT?) -----¢¢ The PLUGE BARS (which are the¢ small rectangular bars just below the¢ long vertical color bars) are use to¢ set monitors that have the capability¢ to show only BLUE. If yours does not¢ have this feature (most home monitors¢ do not), you may skip this section.¢¢ HOW TO USE PLUGE BARS!¢¢ To use PLUGE, set your monitor to¢ the BLUE ONLY position, and adjust the¢ CHROMA (color) control, until Bar #1¢ (top left) and Bar #7 (top right)¢ match the PLUGE bars below them in¢ luminance level.¢ Then, adjust the HUE (tint)¢ control until the two inner bars (#3¢ and #5) match the PLUGE bars just¢ below them. When you return to normal¢ video, your color and hue will have¢ been set correctly.¢¢ WHITE REFERENCE BAR¢ -------------------¢ The WHITE REFERENCE BAR (the big¢ square block at the bottom of your¢ screen) has a luminance level of about¢ 90% (the real reference bar is 100%,¢ but the Atari can't generate more than¢ 90% luminance) and should be a PURE¢ WHITE. It should appear just slightly¢ brighter than Bar #1.¢¢ LUMINANCE LEVEL¢ ---------------¢ Luminance level is generally¢ unimportant to a user without a¢ luminance meter. If you do not own a¢ luminance meter, you will have to¢ eyeball this one.¢¢ HOW TO USE LUMINANCE LEVEL!¢¢ This is done by removing all¢ color from the screen (by adjusting¢ the COLOR or CHROMA control to its¢ lowest point).¢ Then, using the CONTRAST control,¢ adjust the screen to what you¢ determine as an acceptable viewing¢ level.¢ Then, adjust the BRIGHTNESS or¢ BLACK LEVEL control so that the BLUE¢ bar (#7) is just indistinguishable¢ from the background color. You should¢ now see even steps of decreasing¢ luminance from left to right.¢ If not, readjust the CONTRAST and¢ BRIGHTNESS until you see this¢ progression.¢ Finally, readjust the COLOR or¢ CHROMA control so that the colors do¢ not appear too saturated. ¢ Oversaturation, if it exists, will be¢ especially noticeable in the RED (#6)¢ bar.¢¢ --------------------------------------¢ Following the steps above will give¢ you a happy and well-adjusted set.¢ <-> <->¢
