Why do some Landsat browse images appear pixelated or have a color shift midway through the scene?

Pixelation is an artifact of the browse generation process and is common for scenes that are located over flat, low-contrast areas, such as water, sand and snow. The actual data will not appear this way.

A linear shift in color midway through a scene is due to gain change in the sensor, which occurs when the sensor encounters an area of consistently different reflectance (for example, when the sensor encounters snowy regions or highly reflective desert areas). This will be visible in the browse images because these are created using raw uncalibrated data, but should not exist in the Level 1 processed product. (There may be a single residual scan line of altered Digital Number (DN) values in the affected band(s) at the location where the gain change occurred).

A calibration parameter file (CPF) containing gain change information is used during processing to incorporate the appropriate gain and bias values.