Xerox 4760 manual Compress transfers, Quality, Subsampling, Compression

Compress transfers

Select this option to have the scanner compress the image in Gray and Color scans. This reduces the file size and allows for faster image transfer from the scanner to the computer. Once the compressed image is on the computer, scanner’s driver will then uncompresses the image, and perform any image processing functions that have been selected in the scanning interface. The uncompressed image is then transferred to the scanning application. With Compress transfers, a scanning application such as Nuance PDF Converter, will receive the uncompressed image and save the image in whatever file format it uses. You can use the Quality slider to adjust the level of compression you want to use.

When the Quality option is set to High quality, there is very little visual difference between a compressed scan and an uncompressed scan. When the quality option is set to High compression, there may be a greater visual difference between compressed and uncompressed scans.

Quality

You can fine tune the compression level by adjusting the quality slider between high compression and high quality. When the quality level is set to high compression, the scanner will scan and transfer images faster than high quality, but the image quality of the output scan will be lower.

Subsampling

The subsampling options allow you to select the encoding ratio between color information and luminosity. Subsampling works by lowering the resolution of the RGB colors found in an image without affecting luminescence of the image. This compresses the image to create smaller file sizes but it can sometimes result in loss of image quality. Depending on the type of image being scanned, subsampling encoding may not have a noticeable affect in the final image file. You should try test scans using the different levels of subsampling to make sure you are happy with the image quality.

•4:4:4—no subsampling and the ratio between color and luminosity remains unchanged.

•4:2:2—mid-level ratio between color and luminosity.

•4:1:1—highest ratio difference between color and luminosity, which results in saving the smallest file size.

Compression

This option is specific compression for file and memory transfers to an application. It is only available if the application you are using can accept a compressed image file. For instance, if your scanning application is set to receive JPEG compressed images, then the Compression field will display JPEG. Otherwise, the status for Compression will always be disabled and display Uncompressed because the scanning application you are using is requesting an uncompressed image.

The Compress transfers option described herein compresses the image for faster transfer from the scanner to the computer. The driver uncompresses the image and transfers the uncompressed image to the scanning application. The Compression option will often be disabled as most applications do not support receiving a compressed image file from the scanner driver.

When this option is available, it is an advanced user and application option and should not be adjusted if you are not familiar with the technology. However, if you are certain that you are using an application that can receive a compressed image, and you want to be able to change the image compression type, you will need to enable user adjustable compression in the scanning interface. Please refer to the Driver Settings section for instructions.

Please note that if you adjust this setting, and the application cannot actually accept the option you change, the scanning interface and the application may crash. It is highly recommended that you leave the default options and let the application set any image compression.

Xerox® DocuMate® 4760	159
User’s Guide