Quote Originally Posted by ChristopherCoy View Post
Are you trying to say that what I did basically averages out to grade 3 at 10secs?
Almost. You can convert the duration of the two exposures, that is time in seconds through the blue (thard) and the green (tsoft) (or magenta and yellow) filters into the resulting, actual grade. You would need to calibrate the formula to your filters, but for the Ilford grades produced by Ilford 500H head which I use, with its original, dichroic filters, the formula is:

Resulting Grade = 3 x Log10 (thard/tsoft) + 2

For example, if your hard filtration exposure is 10 s, and the soft one is the same, at 10 s, the grade = 3 x Log10 (10/10) + 2 = 3 x 0 + 2 = grade 2, using Ilford ISO (R) grading. To calibrate the formula, if grade 2 happens to require uneven durations of hard and soft exposures, multiply thard (or tsoft) by a coefficient that will make their fraction equal to 1.

Burning with different grades is a great tool. Split printing can help select intermediate grades for which you have no fixed filters or settings.

Having said all of that, if the practice of split-grade printing makes it easier for you to print, or to learn how to arrive at the grade and the base exposure, use it. For some, they stick with it forever, creating wonderful prints. Others find it can lead to missing out on softer prints and yielding more contrast than needed. It's a tool.