Most consistent developer method

[Bruce Watson]

Bruce
I have come to understand that some developers (Rodinal for one) will increase the Mackie line effect with lesser or no agitation. I look foreward to someone coming through with the science part, but I'm sure many folks will have some practical experience.

No doubt. Just as there are many who have practical experience who believe that agitation increases graininess. The science says otherwise; we know now that agitation has no direct effect on graininess. But if you increase agitation while keeping everything else constant you normally increase density somewhat. And density is directly related to graininess. So while there appears to be a link between agitation and graininess, in fact the increase in graininess is caused by a corresponding increase in density, and agitation has nothing to do with it.

One of the things that science is really good for is separating belief from fact. That's why I really want to see the science on Mackie lines. What I normally do is look stuff like this up to verify and/or correct my thinking, and it's frustrating to run into the edge of knowledge like this.

[sanking]

There is absolutely no doubt but that some developers when used with reduced agitation will produce greater adjacency effects than when used with constant agitation. There is plenty of good science on this. Start with Grant Haist, Modern Photographic Processing, Volume I, pp. 408-14, and references.

Some experts, Richard Henry for example, found no evidence that type of agitation had any effect on adjacency effects but closer reading of his methods show that his method of testing did not allow the film to rest long enough. Moreover, the issue can be clouded by the fact that some types of developers better than others at producing the line effects.

If one is printing directly from a negative in the wet darkroom, either by contact printing or by enlargement, development for the proper edge effects is an important tool. However, if one is developing film to scan the issue is less important because the use of unsharp mask in PS can increase sharpness in the same way that edge effects increase sharpness.

Sandy King

[Bruce Watson]

There is absolutely no doubt but that some developers when used with reduced agitation will produce greater adjacency effects than when used with constant agitation.

After more research I think I can confirm that this is in fact the case. Sandy, how could I ever have doubted you? Sigh... I can drop my stubborn stance with respect to this phenomenon, with some qualifiers.

What I found is that agitation alone isn't enough. There are at least two other factors. One is silver iodine content in the emulsion. The other is low bromide content in the developer. Apparently a developer with low bromide content can cause the formation of Mackie lines in a film with low silver iodide levels, but at considerably lower levels than it would with a film of higher silver iodide content.

So... more modern faster films with higher silver iodide content are more likely to show edge effects. Older developers with less bromide are more likely to show edge effects. And neither will show much in the way of edge effects without stand or semi-stand development.

It was explained to me that there's a thin line between edge effects and bromide drag and that both are considered to be "agitation defects" caused by insufficient agitation. Bromide drag is actually considered to be the "smearing" of Mackie lines due to insufficient agitation.

Apparently, if you really want to see Mackie lines on your film, you should use a modern fast film and an older low bromide developer, and a stand development technique. You'll likely get other agitation defects too, like halos around fine details and who knows what else.

Finally, I speculate the reason that research into this phenomenon isn't well represented in the literature is that it's considered a defect due to improper agitation techniques. The "cure" is proper agitation, and this is hardly worth the writing and publishing of papers in appropriate scientific journals. IOW it's the users who want to exploit this particular "defect" who are interested in this, the researchers themselves know about it and mostly dismiss it.

[sanking]

Bruce,

Very good summary. I agree with your comments about the importance of silver iodide content and the significance of that for modern emulsions. I have been able to get very enhanced adjacency effects with Tmax-100 film developing in either Pyrocat-MC or -HD at a dilution of 1.5:1:200 with agitation every three minutes, after initial agitation of one minute. I also got really impressive adjacency effects with HP5+ and TMY.

On the whole adjacency effects are more useful for people who contact print LF and ULF negatives with a wet process. I don't consider edge effects to be a "defect" but it is very easy to go from edge effects to bromide drag which will cause streaking between areas of tonal extremes. BTW, one of the persons who has really mastered semi-stand development and edge effects is Steve Sherman, who published a couple of articles on the subject a few years ago in View Camera. There were a few very informative threads on the subject about three or four years go on Michael Smith's AZO forum.

If you scan it is likely that you won't pick them up with a consumer type flatbed but I think you might with a drum scanner used at high resolution.

Sandy

[ki6mf]

I would opt for a diluted developer that mandates longer development times. I use D76 1:3 and normal development time is 14 minutes (I know sit in a chair). I keep 2 minutes difference per zone/stop. The diluted solution avoids problems when your shortening development times. With straight developers and shorter development times its to easy to overshoot a shortened development times and end up with over developed highlights.