When processing JPEG input files in Color Factory, here's a trick to avoid unnecessarily recompressing the JPEG at the expense of image quality:
On the basic channel settings page, seen below, choose JPEG Copy as the Output File Format.
This format should be used in channels that are used for all other things than editing of image data. It will preserve the image data without decompressing and recompressing it, avoiding JPEG quality loss. Note that the JPEG Copy setting will effectively prevent any kind of image manipulation in the channel, so it should be used in those cases where a channel is used e.g. to route input JPEGs to various output folders, to add metadata and other processed not involving manipulation on the image data. Note that a non-JPEG input file will be converted to JPEG in the output folder with the chosen JPEG Quality setting. Also, a Progressive JPEG in the input folder will be converted to a regular JPEG in the output folder.
Technically, Color Factory will write a new file in the output folder, but the JPEG data block will have been transferred to the new file without alteration.