Delta 100 in HC-110 vs. DD-X

This could get long...

I happened to get a hold of a Jobo Multitronic timer/analyzer. One of the features of the is device is the ability to measure relative negative density, not a true densitometer, but a little better than nothing, right?

I was testing testing Delta 100 with DD-X, since Ilford recommends it, and what I found is that I need to up-rate the EI to ~125 (interesting since most of what I've read is that most films require a reduction of film speed).

Anyway, just for kicks I got out a recent test run of Delta 100 in HC-110 and found that I needed to down-rate the EI to ~64. I used the same equipment etc. that I used in the DD-X test.

I've re-tested the DD-X to make sure that it wasn't an error on my part and I got the same result.

Is this possible? Is DD-X so speed enhancing that it would cause me to have to up-rate the film to get the required densities? Is this Jobo analyzer wrong? Seems correct since I'm seeing a .3 change in the log D for each stop.

Ilford recommends upping the EI with Delta 400 to 500 when using DD-X, and it is a developer recommended for pushing. I don't recall them recommending anything similar for Delta 100 however.

This *would* explain why I like the underexposed bracket shots the best...

DDX is a microphen derived liquid dev, microphen or course being well known as a speed increasing dev.

Tom Stanworth said:

DDX is a microphen derived liquid dev, microphen or course being well known as a speed increasing dev.

Click to expand...

Yes, DD-X and Microphen are both Phenidone/Hydroquinone based developers.

DD-X uses Sodium Tetraborate buffered with Boric acid as the alkali. DD-X uses an organic solvent instead of water (Diethylene Glycol).