Stand film processing
Processing of film is a science. It is all about chemicals and reactions. There is no correct process just one which works for you.
I shall start at the beginning. Many photographers are unaware that there camera measures everything at mid grey. Take three pieces of paper black, white and grey, meter them and take the shot you will get three grey images. So exposure is key to getting good images on film. To this end many people use the Zone System developed by Ansel Adams. Using a 1° spot meter one is able to evaluate the exposure readings of the entire scene. It starts by placing a shadow value. This is an exposure which usually retains fine detail in the shadows. As processing time effects the shadows only slightly this exposure allows the shadow detail to remain similar when changing development times. Highlights are effected greatly by processing times. So after evaluating a scene one can expose for the shadows and develop for the highlights. To increase contrast time can be added to the process or reduced if the scene has to much contrast. Tests have to be made for each film type and notes taken for each exposure. This system works well for sheet film as each image can be adjusted individually.
This does not work for 35mm because of the variation in contrasts throughout a role of 36. So my solution is this. I tend to use an old Weston Master to meter but if using the Pentax I will use the internal meter. I meter for mid grey. The average in the scene. Its quick and easy and experience tells me more or less the best average exposure to take.
Now the fun part. In stand development I leave the film in the chemicals for one hour. True stand development requires no agitation at all. I'm not a fan of it. It is usually inconsistent and can often be uneven and streaky. That's not to say there are people who have not mastered this method. A few are great at it. The idea is that by leaving the film in without agitation the highlights use up the chemical quickly and do not increase in density but the shadows continue to develop slowly and extra detail can be had. My method uses a different logic. Its important to understand that there is an added factor to adjusting the highlights. Agitation.!!! By agitating you refresh the chemicals in all areas something which will send the highlights off the scale if your not careful. So its a balancing act. I use Rodinal developer. I use it 1:130 dilution. The idea is to only have enough chemical for 1 film. I want the chemical completely exhausted by the end of the hour. I never pre wash as I want the chemical to come in contact with the film immediately its poured into the tank. I agitate for twenty seconds and leave the film undisturbed for 10 minutes. I agitate then 3 inversions. I then agitate 2 inversions the next 10 minutes and finally 1 inversion at 30 minutes and one inversion at 40. The last twenty minutes I leave it standing. This method removes uneven processing but does not increase the highlights to a level where detail is lost. The shadows have plenty of time to develop and retain great detail. Its important to note you must have a tank capable of taking two films. Leave the bottom one empty and load the top one. Old chemicals tend to fall to the bottom and fresh chemicals remain in contact with the film. So there are three factors working here. The curve is only being effected top and bottom the central part of the the sensitomic curve actually extends and the bottom and top of the curve are effected by the development. The time effects the shadows and the agitation effects the highlights. The middle remains as you exposed it, unaffected. The beauty of this method is you can adjust the final print contrast using you different paper grades. All the detail is there. The very high dilution is what allows for the long time. Usually we use far more chemical than we need and agitate every minute. It works well if the scene is not to contrasty and we get our exposure perfect. I do not use this method to compensate for bad exposure readings. I use it to supplement my Zone System process which can't be used for 35mm.
I hope this enlightens people to the alchemy of film processing. There are many ways to effect the process and get different results.