Ilford Delta 400 Pro: Over exposed and over developed

I recently "standardized" (that's what the folks at my local camera shop call it) for Delta 400 using instructions from Fred Picker's Zone IV Workshop book. I shot a gray card at Zone I at various ISOs.

I then determined the amount of time needed to achieve maximum black through film base plus fog and determine I needed a minimum print exposure of 9 seconds.

Next I determined which exposure (ISO) rendered a Zone I print at 9 seconds: ISO 250.

Next I shot 3 rolls of 120 at ISO 250 each exposure ranging from Zone 0 to Zone X. I developed the rolls one at a time, the first at the recommended development time, and found that my Zone IX print was too dark at 9 seconds. I developed the second roll for 25% longer and Zone IX was too light. The third roll I developed 15% longer than the recommended time and got a good Zone IX print.

I've ha good results with under exposing and over developing (compared to Ilford's recommended times) but I expected to have to under develop them film considering I had over exposed it. Anyone else have a similar experience?

rkOliver.

Hi
The lover your Expose Index you have, the more light you give to the film, and higher will the density be. That is for all zones, from zone I to X. That means that your zone IX will have more density than if you had exposed the film with a higher E.I.
That mean you have to develop for less time to get a good zone IX density.
- Yes, if you "over expose", you have to cut down the development time. (I would not consider right E.I to be over exposing)
(Which developer do you use?)
- sorry for my english.

- OM

Was this an Ilford developer and did you use the Ilford recommended time for EI 250? If it was then maybe depending on your method for exposure, development etc, the 15% extra is within normal tolerances. I take it that you didn't use the recommended time for ISO400.

What counts is whether the negs are right for your way of doing things? Most experienced and acknowledged experts such as the late Barry Thornton and others say that box speed is overrated( your experience being the same) and recommended times are overstated( your experience not being the same). However there are others, Roger Hicks being one, I think, who say that their findings are that 10% more dev. time is best for them.

pentaxuser

Ilford's recommended times are determined in a laboratory using calibrated equipment.
By using the zone VI method you are calibrating your equipment and methods to the materials.
Your experience with the dev time is similar to mine, also using the Zone VI method.
I wouldn't worry too much that your results are slightly different than what you may have expected. The point is not to confirm your expectations, or even anyone else's results. Shoot some pictures of familiar subjects exposed and processed according to your test results and see what the prints look like, then decide if you are off where you'd like to be, or not.