Selenium toning of negatives - variations in colour

<p>I've been doing some experiments with selenium toning of negatives. One film (let's call it the good film) I have gives a lovely deep purple in the shadows. Others turn out much more sepia, more turd coloured. I prefer the former.</p>

<p>The problem is I can't determine the difference. The films are the same (Neopan 400), with the same development, the selenium toner is the same bath (although I've tried different concentrations and there's no effective difference between 1+3 and 1+19).</p>

<p>In my experimentation I notice I can get the nasty brown colour from the 'good' film if I bleach for a couple of seconds in a ferricyanide/bromide bath (first part of a sepia toner process) to turn some of the silver back to silver bromide, so I figured it might be something to do with poor fixing in the 'bad' films.</p>

<p>But I've tried re-fixing the 'bad' films and that makes no difference - there's nothing I can do to get the nice deep purple colour like I can for the 'good' film.</p>

<p>I hope I've explained this ok - has anyone any suggestions for something else determinative of getting a purple colour vs. getting an ochre/sepia colour?</p>

<p> </p>

<p>Unless you are going to printing color, why are you trying to achieve a certain color? Toning of negatives is generally done only to intensify or for archival purposes.</p>

<p>you may be cross contaminating chemicals (bleach and selenium) causing an undesired outcome. not sure, but it seems possible.</p>

<p>Yes, indeed color makes little difference. You may also want to try a staining developer on the front end instead--a Pyro developer.</p>

<blockquote>

<p>Unless you are going to printing color, why are you trying to achieve a certain color? </p>

</blockquote>

<p>I'm developing the film to positive (develop, bleach, clear, fog, redevelop) as the final product - but that's not particularly relevant. Please be assured that I *do* actually want to tone the negative. (It's soooo frustrating when you ask a question for a particular reason and most of the replies assume you must be an idiot, wasting your time, and/or doing completely the wrong thing.)<br>

Tim - thanks.</p>

<p>Well Alec, if you had of said that in the first place your answers might have been different. It's so frustrating when people ask questions but fail to give all the infomation they already have. I won't answer you oringinal question as I have no desire to tone my negatives and have never tried.</p>

<p>Sounds like bad fixer or not enough time in the fixer to me. Always use a fresh film fixing bath if you're going to tone these. Re-Fixing won't correct the problem no matter how much you do it.</p>

<p>Alec, most participants on this forum are very willing to help in any way they can. But your request is unusual. I can't recall ever reading a previous discussion, or article in a book or magazine, about selenium toning negatives specifically for the purpose of producing a purplish tint. So it's reasonable for others to inquire about what you're trying to accomplish so that they can help offer suggestions.</p>

<p>In the past 10 years on this forum, virtually every mention of purple negatives has been related to requests to eliminate the tint caused by the residual dyes (anti-halation and sensitizing) in some films.</p>

<p>While some selenium toners will produce a distinctly purplish tint on prints - sometimes described as aubergine for the resemblance to the purple eggplant - I've never seen this effect on my negatives. I've treated some of my negatives in Kodak Rapid Selenium Toner and Paterson Acutone (the latter is more coppery warm than purple) and I've never seen any color change in the negatives. There is some intensification, but the primary reason for selenium toning negatives is for archival permanence.</p>

<p>If you want distinctly purplish negatives you may need to use a selenium toner know for that tint - KRST - and a film that tends to retain the purple tint in processed negatives. Some of the T-Max films do this, and the current version of Tri-X tends toward a slight purplish tint rather than the steely gray of previous decades. You might also see whether any of the Berg toners might be suitable for your purposes.</p>

<p>Alec,<br>

While I, too, think your response above uncalled for (if you don't want be thought of as immature or an idiot, then maybe try not acting that way?...), I find your project interesting and will give you what knowledge I have about the subject.</p>

<p>First, I used to tone negatives regularly as a contrast-increasing measure. Sometimes the tone (color) of the negative changed, sometimes it didn't. I believe the factors that control negative "tone" would be similar, if not identical, to those that influence paper toning. A list of those follows for your perusal and cogitation. Possibly, by manipulating one of the variables available to you, you can achieve satisfactory results.</p>

<p>The largest factor in whether silver in a developed emulsion will tone or not is the original composition of the halides, i.e., the relative amounts of silver chloride, bromide and iodide. Bromide emulsions tend to tone more rapidly and deeply. Films, unfortunately, are largely chloride and iodide, and will likely not tone much. The fact that you have achieved toning to your liking on a negative is, however, reason for optimism. That said, if I understand correcty, you are using a rehalogenating bleach and redevelop technique to get a reversal of tones and a positive end product. In that case, the composition of the emulsion is dependent on the rehalogenating agents in your bleach.</p>

<p>The next important factor is the developer used. Different developers, or even dilutions of the same developer, will affect the toning characteristics of an emulsion. The developer you use for redeveloping can play an important role here. Another extremely important factor is the dilution of the toner. The freshness of the toner solution can make a big difference as well. Also, processing and work flow make a difference. Complete fixing is very important.</p>

<p>So, now on to some specifics. If I gather correctly from you original post, you are using the same film (Neopan) and developing (and redeveloping) the "good" and "bad" negatives identically. If so, and you get different results from toning, it is not a question of emulsion or developer formulation/dilution (although manufacturers change film formulations without notice from time to time and developer strength, exhaustion, etc. can make a big difference. In your case, the state of the bleach can as well). The first place to look, then, would be in the toner formulation and dilution and/or your processing. Experiment with different dilutions and times. A stronger solution for less time usually gives a more marked change in tone. Make sure you have fixed adequately in fresh fixer. If you are currently using a wash aid (e.g., Hypo Clearing Agent) then omit it from the processing sequence, it swells the emulsion and may affect the toning. Use of a two-bath fixing sequence as for prints may help. Try both transferring the negative directly from the fixer to the toning bath and washing thoroughly before the toning as this may also have an effect on the toning.</p>

<p>Bleaching your negatives in Farmer's Reducer bath A turns the exposed silver in the emulsion back into silver bromide (this is a rehalogenating bleach). You might try doing the bleach/redevelop step a second time, and/or with a different bleach formula. This will change the emulsion characteristics some and may help you get the tone you want.</p>

<p>Some questions: you mention that your "good" negative (I guess I should be saying "positive," since you are making positives here...) had good color in the shadows, which I am taking to mean in the densest areas. Is there a marked difference in density between the "ggod" and bad" products? Is there anything in the redevelop process that you did differently between the "good" and "bad" positives? Are you using the same bleach formulation/dilution every time? If you are using a ferricyanide/bromide bleach like Farmer's A, play with the freshness and dilution of the solution. This may possibly help the toning. If you really want to display or project the final product with a particular tone, you may even have to experiment with different film and developer combinations.</p>

<p>That's about all I can think of for the moment. Do let us know your results.</p>

<p>Best,</p>

<p>Doremus Scudder</p>

 

<p>Doremus,</p>

<p>Thanks. Actually I think I don't really care what people think of me as long as they have something interesting to say! <br>

The reversal process doesn't use a rehalogenating bleach (oxidiser) just an acidified permanganate followed by a metabisulphate bath to remove the silver. Here's a scan of my notebook with the different colours. Top left is the raw silver, top right is the dark colour I rather liked from the selenium, the bottom left is the more sepia-like selenium that I don't care for so much and bottom right is a true two-step sepia tone (halogenation bleach, then thiourea bath).</p>

<p>I've tried some different film stock too. I get a much more earthy red result with HP5+. I'm also trying different formulations for the first developer. </p>

<p>I do like your idea about inserting a rehalogenation/redevelopment step before the selenium toner. I'll try that out and see if it makes any differences.</p><div></div>

<p>Doremus,</p>

<p>here are the results for a scrap piece of film (positive image) split in four. From the left:</p>

<ol>

<li>un-toned</li>

<li>selenium toned without bleach/redev</li>

<li>bleach in ferricyanide/chloride, redev HC110, tone</li>

<li>bleach in ferrcyanice/bromide, redev HC110, tone</li>

</ol>

<p>All the toning was in 1+19 selenium toner until completion (no further visible change, approx 10 mins)</p>

<p>There may be some colour difference between 2 and 3/4, but not much visible between 3 and 4. </p>

<p>I'll keep experimenting and post here if I find anything useful.</p><div></div>

<p>I feel I must respond since it was my comment to which you reacted so negatively.</p>

<p>First off, I never assumed you were an idiot, and I take strong offense to your allegation that I did.</p>

<p>Second, I wouldn't have asked what I thought was a particularly relevant question if your posting hadn't implied that your objective was focused solely on achieving a particularly colored <em>negative</em> . You never mentioned anything about making positives, so it was logical - I thought - to ask why the color was so important. This is a <em>black and white</em> film <em>processing </em> forum after all!</p>

<p>Russ,</p>

<p>You're absolutely right. They're not negatives at all, they're original-film positives. Very sloppy nomenclature on my part.</p>

<p>Apologies for jumping at your post.</p>

<p> </p>

<p>Thanks, Alec. I appreciate that.</p>

<p>Now on to more important matters!</p>

<p>Alec,<br>

 <br>

The selenium-toned positive that you say you like seems to me to only be partially toned.  As with prints, the most pleasing image tone is often achieved long before toning is complete.  I would experiment with shorter toning times and pulling the positive before complete toning occurs.  Use a white tray and good illumination and keep an untoned positive nearby in a tray of water for comparison.  Pull the positive when (or just before) the desired tone is reached.  You could also experiment with dilution a bit; try 1+9 or 1+15 and see if you get different image tones (I do when toning prints). Often a rather strong toning solution with partial toning results in a pleasing split-toned effect, where the shadows take on a reddish/purplish tone but the less dense areas remain relatively untoned.<br>

 <br>

There are a bunch of other toners that may be of interest to you as well (brown toner, etc.), but I'm not qualified to speak to those, as I use them only rarely.<br>

 <br>

Looks like you are on the right track; just keep plugging away and you'll find something you like.<br>

 <br>

Best and good luck,<br>

 <br>

Doremus Scudder<br>

 <br>

P.S: Glad you cleared up the misunderstanding...</p>

<p>I just came across this old thread. I love this comment by Alec:<br>

"Actually I think I don't really care what people think of me as long as they have something interesting to say!"<br>

What a classless thing to say! In other words, you don't care how you treat other people but you want them to be of assistance to you anyway. Wow! <br>

Your response to the initial replies to your question was completely uncalled for and your subsequent remark (above) revealed that you really are immature and obnoxious. You come across as a spoiled, self-centered little baby. Also, your description of your problem was incomplete a poorly worded and anyone reading it would have questions. It seems as if you actually wanted to receive the responses that you got so you could have a hissy fit. You came to this forum asking for help and then you insulted the people who took their time to help you but asked logical questions to determine what you were trying to do. You don't care what anyone thinks of you (based on your rude behavior) and yet you still expect them to help you! Talk about bizarre!<br>

Anyone who could offer helpful advice needed to know what you were trying to achieve but you left that information out.<br>

I would suggest that you simply don't engage in forum discussions in the future based on your comment (above). People are here to help and they spent their time trying to help you with your very unusual problem and you insult them? What a spoiled brat! You have some growing up to do, son.</p>