You need a 31-step transmission tablet in your typical negative format to enlarge it (mine is 4x5, which is also useful for other tests where contact printing is the way to go). If you don't have a densitometer, you also need a 21-step reflection tablet to measure your results.

In the example of my previous message, the target highlight and shadow densities (step 2 and 20 on the 21-step tablet) are produced at step 23 and 14 on the test print (31-step tablet). This makes a difference of 23-14=9, which is equal to 0.9 log exposure range, because each step on the tablet is 1/3 f/stop or 0.1 log exposure apart. In the attached table, you'll find that a log exposure range of 0.9 is equivalent to a paper contrast of roughly ISO 3.0 (0.88 would be exactly 3.0).