Eliminating Image Quality Issues:

Correct Reproduction

This is the correct reproduction of Benjamin that accurately displays his real appearance.

Notice the subtle gradations of skin tone on his checks and nose, the visible detail in his eyes and the naturalness of the fabric of his shirt.  Also note the smoothness and uniformity of color of the background behind Benjamin. 

Ideal Luminance Curve

To achieve the correct reproduction, you will need to reach the 'Target' parameters in all of the ColorFacts Instruments.

When you have reached the correct reproduction point, the Luminance Histogram in ColorFacts will display a gamma characteristic close to 2.5* with both ends of the luminance curve going into opposite diagonal corners of the graph.

Brightness Too High

In an attempt to create a brighter picture, the Brightness control of this display has been set too high. 

Ironically, the increased brightness actually decreases the dynamic range of the display, and will cause the picture to appear washed out and incapable of reproducing proper shadow detail.

Luminance Graph Elevated

Here you can see that the left-hand side of the luminance plot does not start all the way at the bottom of the graph, but slightly above.  That means that a good black level could not be reproduced.

The elevated black level has also caused the Gamma calculation to be shown as being too low (1.78), and a low Gamma factor is a general indication that the image will appear "washed out" to the eye.

Contrast Too High

Typical of displays set up to catch a buyer's attention, the Contrast of this display has been turned up to an excessive degree.  Initially, this appears to create additional "punch" in the image, but extended viewing of the picture becomes quickly fatiguing, and possibly even damaging to the display device itself.

Note the complete loss of detail in Benjamin's cheeks and nose as the highlight details are crushed.

Luminance Graph "Crushed"

The ColorFacts Luminance Histogram shows that the luminance rises correctly out of Black, but rises too fast and reaches peak White at about 80% of the way up the Gray Scale, causing all details above this point to be "crushed" together.

The Luminance Histogram line should display a smooth transition into the upper right-hand corner and not bump into the top of the graph at all, except at the extreme right corner.

Color Too High

The "Color" setting of this display has been turned up too high, possibly in an effort to make the display appear "richer" and more saturated.

One sign that the "Color" control has been misadjusted is when male subjects appear to be wearing bright lipstick instead of having natural lip color, or if normally fair skin appears sun burned.

Split Color Bars Incorrect

The "Color" setting needs to be adjusted while using the "Split Color Bars" test pattern in the "ColorFacts Test Patterns" program.

The two outside bars should appear as solid Blue bars through the ColorFacts Calibration glasses, and should not be broken into three parts as they appear in this picture here.  Adjust the display's Color control until the bars are a uniform Blue color.

Color Too Low

The Color control is again misadjusted in this picture.  This time the Color control is too low, causing the image to appear undersaturated.

At an extreme, adjusting the Color control too low will result in a Black and White image.

Split Color Bars Incorrect

The "Split Color Bars" test pattern will display the opposite error from the previous example (where the adjustment was too high), but will again display the two outside bars as being misadjusted. 

See the "ColorFacts Test Patterns" Help file for more detail on this test pattern and how it works.

Temperature Too High

Many displays are set up to look their best in store showrooms, and not in your home.  Among other things, this means that the Color Temperature is typically adjusted way too high, which means that the image contains an excessive amount of Blue in the picture.

Although this look may work well to help sales in the showroom, it does not help with our suspension of disbelief when watching at home.

Temperature Histogram Reading High

ColorFacts will display this error as an elevated line on the Temperature Histogram.  Here you can see the dotted line goal of 6503 Kelvin, and this display's actual color temperature of closer to 9300 Kelvin.

The solution is to use ColorFacts and a color analyzer to calibrate the display to D65, which is 6503 Kelvin.

Temperature Too Low

If a display has a "Color Temperature" setting and it is adjusted to the "low" position, the image may not be correct for normal color video.

The picture to the left makes Benjamin appear in unnatural Sepia tones.  Although it lends an air of apparent nostalgia to the image, it is not a correct reproduction.

RGB Histogram Line Separation

Besides using the Color Temperature Histogram (above), the RGB Histogram will also inform you of Color Temperature errors.

Here, we see that all three color lines are very linear, indicating good gray scale tracking.  However, Red is above 100% and Blue is below 100%, indicating that the overall Color Temperature is incorrect.  Recalibrating so that all three lines are at their target of 100% will ensure the correct reproduction (see final image on this page).

Sharpness Too High

A small amount of Sharpness boost (edge enhancement) may not negatively affect the image to an appreciable degree, but it must be understood that this is information that is not coming from the source material, and therefore may affect the "suspension of disbelief" that we would have if the image were more correct.

However, here the Sharpness setting is clearly too high as can be see from the white shadow to the side of Benjamin's face.

Using the ColorFacts "Sharpness" Test Pattern, you will be able to see the visible edge enhancement being performed by the display.

The Sharpness should be reduced until the Black lines on the Gray background are no longer glowing with White fringing.

The only two colors in this test pattern are Dark Gray and Black.  Lighter colors should not appear from the Sharpness control being set too high.

Gamma Too High

The luminance of the image across the gray scale is very important to proper image reproduction since the luminance represents such a large part of our image information.

Here the gamma of the display is too high, which means that the mid-tones of the image are too dark.  Note that the luminance of White and Black are still correct and that the color is still where it should be.  Only the luminance of the mid-tones is incorrect.

Gamma Curve Too Deep

In the ColorFacts Luminance Histogram, we see this display coming out of Black on the left-hand side of the graph very slowly.  The luminance is hardly moving at all below 40 IRE.  The gamma was calculated at being close to 4.2, far too high for accurate image reproduction.

This will result in an image that appears overall "too dark", although neither the Whites nor the Blacks are completely crushed.  The gamma target should be between 2.2 and 2.5.

Gamma Too Low

If the luminance through the mid-tones is too bright, the image will appear "washed out" and will not have the depth that draws a viewer in to the image.

A low gamma setting can appear visually similar to having the Brightness control set too high. 

Here the ColorFacts Luminance Histogram shows that the mid-tones are too bright and the gamma was calculated at 1.8, which does not properly account for the encoding of the source material.

The image will appear even more washed out if the display is the primary illumination in an otherwise dark room.

Poor Gray Scale Tracking

Non-linear gray scale tracking is a common problem, particularly with digital display devices.  The issue is that different levels of gray are different colors.

In this picture, the background behind Benjamin has a slightly Bluish tint to the darkest gray scale shades, turns Greenish through the mid-range, and ends up with a Reddish tint toward the top.

Note how difficult these patterns would be to determine visually using just the picture of Benjamin (without the gradient background).

The ColorFacts RGB Histogram graph is again a powerful tool for discovering gray scale color trends.

This graph shows what we witnessed visually: Bluish at the bottom end, Greenish through the middle, and Reddish at the top.  However, we can now see exactly what adjustments need to be made at various locations in the Gray Scale to correct the image. 

Fixing non-linear gray scale tracking can have a major impact on the believability of the image.

Incorrect Tint

Tint affects the proper decoding of color information in the image and an incorrect tint setting will cause all color information to be shifted.

Tint can be set using the ColorFacts Test Patterns "Split Color Bars" pattern and Blue calibration glasses.

When Tint is set correctly, the two middle bars will be a consistent shade of Blue from top to bottom.  Here, we can see that the middle two Blue bars are broken into three sections, indicating an incorrect Tint setting.

After all adjustments are made, we reach the state of an accurately reproduced image.

Notice from the image to the left how much more "present" and believable Benjamin appears.

A properly calibrated image naturally assists in our "willing suspension of disbelief".

At the top of this table, we showed what the Luminance Histogram will show for a properly calibrated display.  Here you can see how the color tracking appears.

All three primary colors are tracking perfectly with the goal at 100%.  Although there is only one calibrated state, you will know you have reached it when the RGB Histogram displays a graph like this.

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