Depending on the adjustments (if simple enough) i can recommend
irfanview for bulk adjustments and color (and other) conversions.
Open one image, adjust colors to how you like it and make a note of the used values. Color balances/contrast/gamma/saturation will usually be your most used parameters.
Then open image again, press B (for batch), add all files, set your advanced options and start batch. Don't forget to choose the output folder (and rename if needed)
It will look something like this:
Irfanview is also really good as an image viewer. Lightweight, free, a lot of options, and pretty simple to use. i've been a big fan for years!