Kodak Tech Pan and Technidol

<p>I have about 20 rolls of TP 120 that I would like to use. Also, several very small bottles of Technidol developer. There are no instructions with the developer - just an indication that each bottle should make up 600ml of solution. Can anyone tell me if this is then ready for use? or should be diluted further?</p>

<p>Yes, you use the Technidol at the stated dilution. Kodak says you can reuse it once, although I never tried that, and you can only store it for a week after it's mixed.<br /> How many bottles is "several"? If you get the reuse thing right, you will need 8 bottles, according to Kodak <a href="http://www.kodak.com/global/en/professional/support/techPubs/p255/p255.pdf">(link)</a>. Otherwise, you might need 16-20 bottles.</p>

<blockquote>Preparing a Working Solution:</blockquote>

<blockquote>Mix your liquid developer according to the instructions packaged with the developer. Use water at 68 to 86°F (20 to 30°C).</blockquote>

<blockquote>To process one roll of 135-36 film, make 8 fl oz (237 mL) of developer solution. Stir until the solution is completely mixed. To process one 120-size roll or two 135-36 rolls of film in the same process, prepare one pint (16 fl oz [473 mL]) of developer.</blockquote>

<blockquote>You can reuse the developer if you increase the development time of the second process by 1 minute. Store the developer in an air-tight bottle, and use it within a week.</blockquote>

<p>thanks Joseph, it doesn't go far! Not enough to be viable as I've only got 2 or 3 bottles. I thought (hoped) it might be like HC 110 - where the stock solution can be substantially diluted. Oh Well.</p>

<p>I've reused it once and it works well a second time. The color of the developer changes but it still seems to work. I find though that the technidol packets I have results in an amount which is too little volume for two single reel loads so where normally you should be able to get two "doses" of technidol that can each be used twice, what you really get is 1 slightly oversized dose that can be used twice. Since it's unobtainable these days, it's worth reusing.</p>

<p>I think it's set up for the old metal developing reels in the small metal real holders with the metal or plastic tops. Those are small enough to fill up twice with the standard dilution of Technidol. It's really a low energy developer but it works well with Tech Pan. I still have a lot of this stuff in the freezer and a fair amount of technidol too.</p>

Just an added note for something I just found out here in 2018 which may be of use to someone (or not, not sure). I was reusing technidol after 9 days (not the 7 days they tell you is safe) at the +1 minute setting for Tech Pan (so 10 minutes). When you mix it it is clear. When you pour it out of the developing tank the first time it's pale violet. When I stored it, I stored it in a dark purple drinking bottle (all I had) in the back of the cabinet. 9 days later it had turned pale yellow. I was concerned that this might mean it no longer would work but I tried it anyway. When it poured out, it was a medium caramel color (much darker than it did last time).

 

All that said, it worked fine after 9 days even with the pale yellow color change.

When you mix it [technidol] it is clear. When you pour it out of the developing tank the first time it's pale violet. When I stored it, I stored it in a dark purple drinking bottle (all I had) in the back of the cabinet. 9 days later it had turned pale yellow. I was concerned that this might mean it no longer would work but I tried it anyway.

 

Hi, just fyi films and papers typically have various dyes built into them; perhaps to modify the spectral sensitivity, or to "mop up" scattered light, etc. So the color change in your developer may well have been such dyes washed out of the film rather than an actual change in the developer itself. Again, just fyi.

I'd like to know the reasons just from curiosity. I expect there probably aren't many people left with knowledge of Technidol specifically though. Thanks for the tip though. Maybe that is the solution. Usually in the past, I've run into tints put there by Kodak to indicate something to the user -- Indicator Stop Bath for instance that signals exhaustion by color change (which matters a lot more in printing than developing since typically I don't reuse it). I thought the changes might be meant to tell me something, but I have the tech sheet and there's nothing in there that discusses color. Since I didn't check the color in that 9 days, I don't know if it changes from pale violet to pale yellow soon after being stored or if it changed closer to the week Kodak indicated so it's hard to tell if it is intentional. It didn't seem to have an negative consequences though since things worked fine

 

Tech Pan is annoyingly slow as a film, but it's a pretty amazingly fine grained film -- assuming you use Technidol to develop it, or you can make it from chemical formula. I don't know how to do that but I bet someone does. I might get a lot more interested in that when I run out of Technidol.

 

That color change really weirded me out.

Many films have a pinkish sensitizing dye that comes out in the developer.

 

Actual dead (oxidized) developers are usually very dark brown, so light tan is usually fine.

 

I am not sure about the interaction between oxidation products and sensitizing dyes.

 

Diafine, which normally has a long life, warns about the colors and tells you to ignore them.

The dyes are pretty strong, so it doesn't take much to make it look pretty pink.

 

The T-Max films are especially known for their dyes, and even with normal fixing the film sometimes comes out pink.

You can either fix more or ignore it.

 

Also, HC-110 (F) gives close to the gamma of Technidol.

What does it mean to be close to the gamma of Technidol?

Gamma correction - Wikipedia

 

Gamma correction, or often simply gamma, is a nonlinear operation used to encode and decode luminance or tristimulus values in video or still image systems] Gamma correction is, in the simplest cases, defined by the following power-law expression:

 

I hope that clears that up o_O:)

Different gamma.

 

Gamma is the slope of the characteristic curve, or, the numerical value of contrast.

Kodak calls it contrast index on the data sheets.

 

Well, maybe not completely different.

 

For CRT displays, the beam current is not linear in the grid-cathode voltage, and for convenience the correction is done once, by the broadcaster and not in each individual TV set. This is called gamma correction.

 

But gamma is the favorite for power-law behavior, and so is the slope of a log-log plot.

 

For film, low gamma means low contrast, which for TP means more usual contrast.

 

http://wwwru.kodak.com/RU/ru/professional/support/techPubs/p255/p255.pdf

 

The numbers on the little graph are different from the ones on the curves.

 

As for Technidol, it is around EI 25 or so, and for the appropriate development time,

not so much more contrast than Technidol.

 

I have some TP and HC-110, but haven't tried this yet.

Gamma is the slope of the characteristic curve, or, the numerical value of contrast.

Kodak calls it contrast index on the data sheets.

 

Actually different things, although close to the same. Loosely, film gamma is the slope of the "straight line" portion of a film response curve, where film density is plotted vs log exposure.

 

Anyone who has plotted many film curves knows that curve shapes can make it difficult to get a firm gamma value for many b&w films. Kodak's solution for this was to define a "contrast index" based on only two points taken from the sensitometric curve. The contrast index is fairly representative of the film density range that would get onto a conventional print.

 

The difference is probably mostly academic today. Relatively few people work with this sort of thing today.

If the curve has a straight part, or close to straight, then that should be fine.

 

Some of the TP curves have close to no straight part, but go from curving one way to curving the other way.

 

wwwru.kodak.com/RU/ru/professional/support/techPubs/p255/p255.pdf

 

Choosing two points is probably a good way.

If the curve has a straight part, or close to straight, then that should be fine.

 

Well, not exactly. If it's clearly a long straight part, then it's pretty clear what the slope is. But if it has a certain shape in the curve, say a slight "sag" in the lower part, then rolling over for a slight shoulder higher up, you might, for example, say that the important "straight part" is in the lower section, with a lower gamma, while someone else might say it's in the upper part, with a higher gamma. Then I might bridge both of those parts, letting the middle sag away from the "straight line," but sort of splitting the difference. So the "gamma" value is ambiguous; we all get different values.

 

But if we decide to use Kodak's contrast index, we'll all get the same value.

 

Like I said, it's probably mostly academic today, but in the past I've done lab QC work where these were significant things.

So does all this imply that HC110 is a viable alternate developer for Tech Pan?

 

I've seen negative density graphs in connection with Kodak HIE (infrared) film. The idea was that depending on where on the graph you end up, on the middle line, on the top shoulder or on the tail, the resulting IR photograph would change in character. Not necessarily bad, just different. More or less grain, more or less of a ghostly sense, and so on.

 

Tech Pan's problem (or rather purpose) was very high contrast copy photography. The Technidol actually lowers the contrast a lot, or so I'm told. So presumably if you couldn't use technidol or reproduce it, you'd want to lower the contrast in a way that say D76 would not.

So does all this imply that HC110 is a viable alternate developer for Tech Pan?

 

I've seen negative density graphs in connection with Kodak HIE (infrared) film. The idea was that depending on where on the graph you end up, on the middle line, on the top shoulder or on the tail, the resulting IR photograph would change in character. Not necessarily bad, just different. More or less grain, more or less of a ghostly sense, and so on.

 

Tech Pan's problem (or rather purpose) was very high contrast copy photography. The Technidol actually lowers the contrast a lot, or so I'm told. So presumably if you couldn't use technidol or reproduce it, you'd want to lower the contrast in a way that say D76 would not.

 

The contrast with HC-110 (F) isn't quite as low, but should be low enough for many uses.

 

As I haven't tried it yet, I don't think I should actually recommend it. Some day ...

 

It is well known that underexposing and overdeveloping (pushing) increases the contrast.

 

I suppose it is less obvious that overexposing and underdeveloping decreases contrast.

 

Note the different contrast index with different EI and development time for each developer in the data sheet.

Overexposing Tech Pan means an ISO of less than the stock 25! I still have Technidol but I bet somebody out there knows what the chemical formula of Technidol is. If so, maybe it would be possible to mix. Course maybe you'd need to have the right skills and/or maybe the materials would be hazardous. That said, you need a tripod with this film anyway really. It's just too slow.

You're not going to get both speed and heavy compensation (low gamma) with Techpan 2415 without using Technidol. Using a hyper diluted / high energy diluted developer like HC 110 (dilution F) or Rodinal (1:100 or higher) along with very mild agitation will tame the contrast but at the loss of speed. Even with Technidol highlights with 2415 tends to 'wall-up' a bit, but it sure was a fun film to work with in 35mm.

TP is EI 200 in high contrast developers like Dektol.

Yeah and that's fine if you doing document copying. You lose all the characteristics that make it a good pictorial film (even if that was only a sideline from Kodak's perspective). It's quirky certainly. And it really only works on a tripod with a very good lens. Otherwise you probably lose the detail from trying to handhold it at slow speed.

It is sometimes interesting to see what things look like with high contrast.

 

Somewhere I have a roll I did in Diafine, which isn't on the list, but seems to give high contrast.

I misdeveloped some Tech Pan in D76 because it was exposed at ISO 400 and I didn't want to waste technidol on what was probably going to be a disaster. You can read the story and see some images. Not many came out as scannable. Getting ready to process some film after long hiatus

The problem with high contrast films, is that you don't have much exposure latitude.

 

I believe EI 200 is about right for D-76, and maybe you can push to 400.

 

I do have one reasonably exposed roll, I believe in Diafine, with nice high-contrast

pictures of everyday objects.

Ok, I actually looked it up.

 

For D-76, you only get up to about EI 125, and that is with 12 minutes.

 

With Dektol you get EI 200, and with HC-110 (B) from 100 to 250.

 

Those would have gotten you very high contrast, but they might have

been printable.

They are printable, but have a pretty unique look a long way from the Pictorial style of Tech Pan/Technidol. You can see some as a result of an accident with D76 trying to get some really badly exposed Tech Pan to develop. Getting ready to process some film after long hiatus

 

Not sure what I proved, under the circumstances, but you can certainly see the high contrast.