When I first started printing my prints were flat and muddy. Then I took a course and learned about split grade printing. I wouldn't say I've mastered it but I am able to work towards the results I want. Learning how to make test strips, analyse the results and decide how to make the necessary adjustments. Formulate a workflow that worked for me was another fat penny to drop. Dodging and burning seems logical to me (I paint so it seemed like a natural transcription or similar application in principal)
I would say landmark and pivotal events for me were:
- consistency. Using the same materials and chemistry.
- understanding split grade printing and having this demonstrated to me.
- dodging and burning and having this demonstrated to me.
- toning and in particular bleaching. This was a revelation.
I have multigrade enlarger so I cannot comment on the Heiland device. I guess the principal is the same. Depending on what enlarger you have, it may be easier to get a set of Under the Lens multigrade filters.