Funny you should ask. I'm preparing a short introduction to Edwal 10 and 12, and it should be 'ready for the press' (meaning APUG) in the next month.
Edmund W. Lowe (Edwal) created E-10 as a variation to D-76 back in the mid 1930s. He followed it up with a very fine grain developer with identical properties, Edwal 12. The only important difference between 10 and 12 is that 12 has a much lower pH, and produces a nearly grainless negative negative with today's advanced 400 ISO films like TMY2 and Delta 400.
While one may certainly use them diluted for one shot use,
I prefer both 10 and 12 as replenished developers.
There is a practical difference between 10 and 12: 12 uses PPD, and some folks are unwilling to work with some of photography’s potentially less friendly ingredients. Edwal 10 is just fine.
The image Edwal 10 produces, in terms of granularity, is similar to D-76, although the grain itself seems, to my eye, to be cleaner and more defined. It is a very subtle difference. It is not in any way mushy or soft. It has a neutral acutance. It is not soft, it does not produce exaggerated effects.
The tonal scale is different. Compared to D-76, the lower values are slightly darker, the midtones are the same, and the highlights are brighter. Using TMY2 as an example, E10 produces a shoulder that may be placed with precision at a density between 1.5 and 2.2, depending upon your agitation. E10, therefore, is very suitable for Minimal Agitation techniques. With agitation every minute, you can be safe to assume the curve will be very similar to D-76, with slightly deeper shadows and brighter highlights. E10 DOES give full exposure speed, the contrast rise through the shadows is lower than D-76.
In plainer terms, if I were making a picture where the shadows were more important than the highlights, I would use D-76. If the highlights were more important, I would use Edwal 10. For a balanced scene, either would do very well.
Most of my work is available light portraiture. Edwal 10 and 12 make negatives from TX and TMY2 that resemble studio work with TXP (in conditions that would be impossible to work with TXP). In short, Edwal 10 is a very carefully crafted alternative to D-76 that excels when flesh tones and highlights are important, and when local contrast in the midtones needs to be increased. It is a very good developer to use with incident readings.
For a beginner, or for all around safety, D-76 would be a better choice. Edwal 10 provides a fine second developer; a different look. On an overcast day, or in the shade, Edwal 10 !
Here is a curve from a calibrated step tablet, read through a densitometer and everything. Note that this is for a negative that was given minimal agitation, so there is a pretty dramatic shoulder, as well as more shadow density than one would expect with conventional agitation. But this suits MY work, so here is MY curve ! Hope it helps a little.
Last edited by df cardwell; 02-24-2009 at 03:42 PM. Click to view previous post history.
Reason: typos, errors, and additions.