Just a quick tip to always remember to invert your images when engraving on black or your results may be, unexpected :)
When you import your image into XCS, it will not be inverted, but will look like it will once engraved.
Select the object and click the option to invert. You will see the negative image now.
These were done using the default settings for the S1 in XCS - left shows inverted results, right shows original.
Check your settings and then check them again and save your material from being wasted! :)