A black and white grey curve is a custom curve you add to Photoshop just prior to printing the image.This curve ensures the values sent to the printer match what you see on screen.

Apart from the paper Grey Curves program, you will need a device which can measure print values such as a DataColor Spyder Print, X-Rite i1Po, X-Rite ColorMunki etc

The Full version will automatically generate the final curve for you whereas the Lite version will produce the curve numbers but you will have to manually add them to a Photoshop adjustment curve

Yes, you may install the program on two computers running either Windows or Mac or both

Yes, from either of the spreadsheets, there is a link to online video tutorials.

Yes, there is an option to upgrade from the Lite version to the Full version

A typical workflow for making a custom grey curve goes something like this.

1. Print out the un-tagged step wedge generated by the program
2. Measure the step wedge patches with your measuring device
3. Paste the values into the spreadsheet
4. Paste the values into the paper Grey Curves Program
5. Press the generate curve button