Silver based films have gotten less grainy over the years but there seems to be a maximum sensitivity to light. Beyond that point you're just pissin' into the wind and that point is in the 1250 to 1600 range using the ASA/ISO scale. A few films can give you a decently printable negative at 3200 and a few film/developer combos will produce a useable image at an E.I. of 6400 if you don't need any detail at all in the shadows and blocked up highlights don't matter.
ISO measurement though is based on the straight line portion of the H&D curve, which is the midtones. Praise the Lord that most PJ work was destined for the half tone screen and not the gallery wall because with deadlines looming you didn't always make the greatest prints.
W. Eugene Smith was famous for his ability to coax great images out of hopeless negatives. One of his favorite techniques was the use of potassium ferracyanide to brighten highlights, lighten areas of the print, and increase contrast a bit. He could go through a lot of cotton swabs!
You can also rub the developing print with your hand here and there. The heat selectively speeds up the development in those areas. When DuPont introduced Varigam, the first VC paper, it opened up the ability to do split filter printing, more contrast here, a bit less there, a bump through the #4 to slightly intensify the blacks.
This might all sound just SO primitive to those of you who cut your teeth staring at a monitor screen while chasing a mouse around her pad, and yes, you did get your hands wet, but for the most part we quickly got to the point where we'd look at the image on the baseboard, know which filter and where we'd need help from others, and most of the time the exposure would be good enough to hand the first print off to the editor.
Some very famous photographers did their best work in the darkroom while tokin' away or swigging Scotch straight out of the bottle, nobody bitched about cigarette or pipe smoke in the enclosed space, and a darkroom could be as much a fun place to entertain the young ladies as the Oval office was under Bill Clinton. It gave us something to do while the film was drying or the prints were in the wash. That's one thing I doubt you'll ever be able to do with P-shop on your computer. Not with your wife in the next room anyway. The light-tight door and the gurgling water in the print washer masked a lot of sounds.
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