I really love this video. I've always wanted to know more about this topic. I usually shoot HP5+ at 400 or 1600. I use ilford ddx and adjust the dev time according to the chart on the inside of the box. Ilford is such a great company to work with as a diy amateur photographer. For color I just shoot at box speed because I use a lab for developing color film.
Bret, yes I find Ilford to be be quite user friendly in many aspects. You know, you can still develop the same with your lab but shoot overexposed; would just cost you the same
Is it just me or did the middle of the straight section of that curve looked higher than 1.3?. I was told by someone with as PHD in chemistry who formulated developers for a living that 1 stop difference in exposure doesn't make much difference on a Black & White negative, so I tend not to be too bothered about rated film speed and just use the box speed. I suspect that the vagaries of camera metering systems are more likely to be an issue in most cases. Nice to see you tackling the subject though.
Paul, yea that’s the thing; where the midpoint lies also depends on where you determine to be the ends of the straight bit, very much subjective. I’d say that though you can certainly live with a slightly underexposed neg, you probably want to create the most printable neg in the first place
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