OK. Here goes a hopefully helpful reply.
Agitation - most standard times are based on one agitation cycle per minute. But Kodak and Agfa recommend agitating every 30 seconds. What's the difference? If you agitate more often, more fresh developer will come in contact with the film emulsion, and the result is more overall contrast in the negative. Basically, we can deduce that agitation largely affects your midtones and highlights.
You will do yourself a favor to try for yourself what agitation and time you should use. Here's how you want to do it. Take APX 100 for example; you need two rolls to do this. Set the camera to EI 100, and bracket at EI25, 50, and 100 for every shot for the full roll. Then develop according to the manufacturer's recommendations. If you dig hard, you will find the APX 100 product data sheet somewhere. Then look at the negatives and determine which exposure has "enough" shadow detail for your printing / scanning process. Then shoot the subsequent roll at that EI, whether it be 50, 60, 80, or 100. Now you want to process about 1/3 of the roll at a time. You want to make sure you are able to get the midtones and highlights where you want them.
And - this is where agitation comes in. If you slow down agitation to every second, or even every third minute, the area in the negative with high level of exposure will develop slower. This helps to soften the contrast while getting a long enough development time that any mistakes you make will be less significant. Time and agitation are your friends in making good negatives, and using agitation to control different lighting scenarios is something that will eventually become second nature to you.
Try to explore the potential of one type of film, and see how you can alter the results by using the same developer in a different way. Tweak it, learn it inside out, experiment, feel your way. Eventually you'll be prepared for any lighting situation, and you'll be confident in addressing how you treat each situation and make great negatives that print easily without much, if any, acrobatics in the darkroom.
The recommended development times online are personal, from people with different lighting scenarios, different light meters, different metering techniques, heck different pH in their water supply. All of which affects the outcome. So please do your own testing. And if you are looking for start times, the first roll processed as above will tell you if the recommendation you got was good or not.
The important follow-up piece to this is to print your negatives (or scan if you're working digitally) to really see if you're doing the right thing or not. And do this often. That's how the process comes full circle, that's how you learn to 'see' effectively.
Pushing APX 100? Why? You've got HP5.
Washing film? The Ilford wash sequence of rinse, 5 agitations, 10 agitations, 20 agitations (all with fresh water exchange) and then running water for a few minutes has worked for many.
I do it that way, but use a film washer for about ten minutes after I've done the Ilford cycle. It seems to work for me so far.
Good luck.
I'm sorry if this has been posted before, but I felt like I should have a thread of my own
I'm relatively new to photography, I only started last summer, but I've been trying to learn as fast as I can. Now I want to advance to the next stage and develop my own B&W film.
I have a load of Agfa APX 100, and three 17m rolls of Pan F+ and HP5+, the former of which I would like to experiment with (it was the cheapest out of the batch). Now I've googled for developing times and found some useful charts, but I still have some questions. Here we go:
Is there a specific amount and timing of the agitations as you develop? I'm looking at 9 minutes of stock diluted (whatever that may be) Microphen.
I hear you can wash the film three times instead of using a stop bath, so that's what I intend to do, but how do I use the fixer?
How far can I push APX 100?
Thanks for answering any of these questions, and again, I'm sorry if this has been posted before.