Using Perceptol...

[db1]

I've been told by Freestyle Photo that they will have Perceptol in stock in December.

 

I have been using HP5+, FP4+, and Pan F+ with ID-11 and I am wondering how these

films will be in Perceptol.

 

Any info is appreciated.

[melvin_bramley]

You will lose film speed & have finer grain. My experience was,using HP5, the fine grain came at the expense of sharpness.It was wonderful for portraits.

[kaiyen]

I accidentally shot HP5 at 100 with my Retina IIa a couple of weeks ago. I tried to compensate by using Perceptol stock. I was actually pleasantly surprised. Loss of sharpness wasn't as much as I had expected using the stock solution, and the tonal range was very pleasing.

 

I think that it's next on my list of developers to really try. I just finished my relatively short FX39 testing. So onto F76+ and Perceptol.

 

allan

[ivan_dzo]

It's very fine grained but you lose a full stop of speed. Compared to Xtol it's no more fine grained but slower.

[flying_tiger]

What does it mean by saying ".. lose a full stop of speed"? If I shoot Pan F+ at ISO 50 and use the Mass DEV chart as reference, how do I interpret the "losing a full stop of speed"? Please explain.

Thanks.

[jordan_w.]

Binyuan -- You will probably find that you have very little in the way of shadow detail -- the shadows will go to "clear film" very quickly.

[lowell_huff1]

You don't have to wait; the ARISTA PREMIUM POWDER DEVELOPER is a very similar formula. Both use phenidone as the accelorator.

[ivan_dzo]

Binyuan, what I mean is, that if you expose a box speed 100 iso film at 100 iso you will have little shadow detail. To get adequate shadow detail you will have to expose it at 50iso and develop normally. Hope this is clear.

[flying_tiger]

Ivan and Jordan, thanks for the clarification. I shot 2 rolls of Agfa APX 100: one at ISO 50 and the other at ISo 100. I'll develop them in Rodinal 1+100, 68F(20C) for 18-20 minutes in one tank at the same time. I'll compare afterwards and see if any difference on the negatives.

[bobbyc]

Heard a lot about Perceptol. can't wait to try it out.

[skygzr]

Bobby, I like the image, and I have a question. It looks like there's something reflected in the water on the left, but I don't see any corresponding "real" object above it. You must have used a really interesting filter......

[michael_gudzinowicz1]

David, You will lose at least one stop of film speed, so you may want to restrict tests to your slowest fine grain films. The reason is that an EI 50 film such as Pan F+ usually will have finer grain and better resolution developed in ID-11 at EI 50, than FP4+ shot at EI 50 and developed in Perceptol.

 

If you wish to compare films, set up a "scene" with a white plastic bag and/or a smooth white ceramic object. A slow hi-res film such as PanF+ or T-Max 100 exposed at EI 25 or EI 32 respectively, and developed in Perceptol, will retain the "glassy" tonality. TMX will resemble Tech Pan without the hassles and the quality will rival the next larger format.

 

Mike.

[robatsgh]

Michael G. - I'm presuming (because I'm rather thick sometimes, and have little experience with Perceptol), that you mean that you shoot the film at the derated speed and develop for the time given for the rated ISO? Ie: expose Pan-F+ at ISO25, and develop using the time for 50?

[kaiyen]

Rob,

 

I don't think you can just "shoot at 25, dev at 50." Pan F is pretty contrasty to begin with, and increasing exposure without adjusting dev time will probably give you unusably dense negatives. I would shoot at 25 and reduce the EI 50 dev time by at least 20% or so. Then adjust from there.

 

allan

[robatsgh]

Well, then, what is meant by loss of one stop of film speed? I shoot Pan-F at 50, I grab my bottle of stock Perceptol, and I look up on Ilford's dev chart that for Pan-F at rated speed, the recommended time is 14 minutes for stock solution. Will that or will that not give me proper density and contrast?

 

If so, then why bother with the whole "loses one stop" mumbo-jumbo? If not, then why list that as the proper time instead of one that DOES give you correct density and contrast?

 

I'm not trying to be intentionally stupid, but it doesn't seem to make the least bit of sense.

[ivan_dzo]

I don't think you're being stupid, it's just difficult to understand, so here goes! Basically the longer you develop film, the more contrasty it becomes and the higher the film speed it has. Film speed is defined as the exposure that will give decent shadow detail at that development time. ie speed varies according to how long you develop it. In addition, the time quoted in charts is only a guide for you to start with. So you shoot PanF at 50 and develop at the book time. If the shadows are empty then you need to give more exposure ie rate it at a lower speed. If the highlights are burnt out then you need to develop it for a shorter period. Changing time or exposure will change the other one, so you have to start again. In reality you exposure a number of shots of a graycard (or step wedge) and scan using a densitometer. You do this several times with different development times eg 10m, 12m 15m 18m and plot a chart for each of exposure versus density. This enables you to establish the contrast and true film speed at different developement times. So the last poster is correct. You expose more generously ie slower speed, and cut back the time a bit to get good shadow detail and non-burnt out highlights. Remember though that how you meter is vital. Spot metering of shadow areas is the only reliable way for black and white especially in really contrasty light. Lengthy answer but I hope it helps!

[kaiyen]

<p><i> Will that or will that not give me proper density and contrast?</i>

 

<p>I apologize that things are confusing. I'm not trying to be difficult.

 

<p>Let's say you shoot Tri-X @ 400 in D76, usually. You shoot a scene and you're happy with the shadow detail. Great.

 

<p>Now, if you change developers, you have to deal with the fact that the amount of shadow detail you get will change, depending on the developer. If you use DDX, which generally increases film speed (ie - shadow detail), then you will discover that the exact same scene you shot before now looks different, with increased density in the shadows. To get the same look as before, you could shoot Tri-X at, say, 560 instead of 400.

 

<p>Conversely, if you use a speed-decreasing developer, like Perceptol, you will find that, in order to get the same amount of shadow detail, you will need to increase exposure. Sticking with the Tri-X example, you may need to rate it at 250 or even 200.

 

<p>You talk about density and contrast. If you mean by density in the shadows, then the EI changes listed above are accurate - in order to get the same density in the shadows, you will need to change your EI rating based on the developer.

 

<p>If you mean highlight density, then you're talking about dev time. As with any process, you have to be open to making adjustments to your process. The times that Ilford gives for Pan F, rated at 50, in Perceptol, will be too long if you instead rate it at 25. Ilford has developed that time based on the <U>box speed</u> of 50, even though I just said that the "real" speed will be less than 50. Remember that ISO is based on a very rigid set of tests. Your ability to replicate those exact test situations is low, which is why you have to make adjustments.

 

<p><i>If not, then why list that as the proper time instead of one that DOES give you correct density and contrast?</i>

 

<p>That's the "proper time" if you rate it at 50. What we're saying is that people generally find that rating it at 50 isn't going to be satisfying, regardless of dev time. You can dev it all you want but you aren't goign ot get more shadow detail out of Perceptol.

 

<p>Of course, Ilford isn't going to tell you to rate its own, self-rated @ 50 speed film at something other than 50. That's what they rated it at, so they aren't going to then tell you to rate it at something else. Therefore, when rated at 50, dev'ed in Perceptol, they're going to recommend a time taht gives the best results, even though that EI won't give you enough shadow detail, in all probability.

 

<p>I have no idea if that helped. But I sure did write a lot.<br>

allan

[robatsgh]

Got it. I've been using developers usually described as "full speed" (D-76, ID-11, DD-X, Ilfosol, etc.), and am familiar with the concepts you describe of exposure=shadow, developer/time=highlights, and making necessary adjustments in dilution or agitation to get a full range of detail and tones. From what you're saying basically, "speed enhancing", "speed loss", and such mean the same thing, just moreso. Yes?

[kaiyen]

Basically, yes, it is simply controlling tones, but more so. Since you're using "full speed" developers, all or most of your tones are falling within the range you want. Shadows are lighter than black, and highlights are darker than white.

 

But when you use a developer that significant loses speed, like Perceptol, you're basically pushing that entire set of tones so far over that shadows go to black. The whole thing shifts over. So you then increase exposure to bring your tones back into the range you want.

 

And, as you have discovered, changes in dilution also affect this. Perceptol doesn't _always_ cost you a whole stop. If you dilute it 1+3, for instance, you can probably get more like 30 out of Pan F, maybe even 40.

 

glad I made some sense. I almost confused myself on that last one :-)

 

allan

[keith_tapscott]

Binyuan, the one stop loss of emulsion speed yield with Perceptol is just a guide. The Ilford ISO standard developer is ID11 fine grain developer, this developer keeps the grain to a minimum with out loss of speed yield as marked on the film carton. Ilford Microphen is a speed increasing fine grain developer and can give a true speed increase of around one-third to two-thirds EV steps more than the trade standard ID11/D-76 developers with out increasing contrast although grain may be marginally more noticable.

Ilford Perceptol is an extra fine grain developer, the extra fine grain however is at the cost of slightly less emulsion speed. You don`t get something for nothing. It is best to do a practical test by bracketing your exposures up to one stop or more than the standard light meter reading indicates to help you to find your personal ISO/ASA speed index.

I don`t know where Lowell got the `Phenidone` from though as the MSDS clearly state that Metol is the only developing agent in Perceptol. Kodak Microdol-X is very similar.

[amine_sultan]

The best combo HP5/Perceptol is the following one (use it for contrasty to very contrasty scenes): expose the film at ISO 100 and then process it with Perceptol 1:1 8mn ( first agitation 30s then 10s each mn) at 68? F (20? C). The result is fantastic : no or almost no masking when enlarging. This is an ideal combo for summer days, countries with harsch lights, weddings when using the strobe(if you want some details in bride's wedding dress, right ?)