E6 Homebrew, Chromebrew. Warnig, longer than assumend

[stefan4u]

E-6 Chromebrew

For quite a long time now I’m trying to develop my own E-6 Formular, inspired by the “Watkins factor Cromebrew”

First developer
Sodium hexametaphosphate (Calgon) 2.0 g
Sodium sulphite, anhydrous 39.0 g
Potassium carbonate, anhydrous 14.0 g
Sodium bicarbonate 12.0 g
Phenidone 0.6 g
Hydroquinone 6.0 g
Sodium bromide 2.2 g
Sodium thiocyanate 1.0 g
Sodium hydroxide 3.3 g
Potassium iodide, 0.1 per cent solution 4.5 ml
Water to 1.0 litre
1.0 litre


Colour developer
Sodium hexametaphosphate (Calgon) 2.0 g
Trisodium phosphate crystals 36.0 g
Sodium hydroxide 3.0 g
Sodium sulphite, anhydrous 4.5 g
Sodium bromide 0.65 g
Potassium iodide 0.1 per cent solution 30 ml
Sodium thiocyanate 1.3 g
Citrazinic acid 1.25 g
CD3 11.0 g
Water to 1.0 litre

Look for the entire article at http://opie.net/orphy/photo/dr/wkft-e6.html


This receipt is a good starting point, but far from being perfect. The FD is “to hot”, does include to much sulphite and is (as all hydroquinone developers) not as stable as whished.
The CD pH is to high (too much Sodium hydroxide) which leads to severe color shifts. The resulting slides where quite “thin” as well because there is nearly the double amount Citrazinic Acid used as needed. A minor mismatch is the iodide potion.

I’ve done a lot of investigations and experiments concerning the ratio of CD3, CZA, sulphite, bromide, iodide and pH in the color developer. Most values are not common, except sulphite Kodak claims 5,5g/ltr. In it’s Z6 manual.

Same misery for the FD, only the bromide potion is told in Z6 and stated to 2,57g/Ltr.
Well, well there is a lot of room for speculations and only very few fixed points. So I’ve shot literally hundreds of Grey cards, always on the hood for Information that makes sense.

1. It’s a good idea to replace the hydroquinone against hydroquinone-monosulphate potassium salt. It’s activity stays constant.
2. The afforded Dimezone S is not available for me, I’m still using Phenidone (A), it’s aging is less dramatic as the hydroquinone’s
3. Watch for the pH, it should be around 9,6
4. Bromide potion is given
5. Sulphite has to be reduced for solve less silver, maybe reduce thiocyanate to 0,8g/L as well

6. Where are all my sheets??
7. Reduce the amount of Citrazinic acid to something about 0,6g/Ltr
8. The CD is VERY pH dependent, the given amount leads to a greenish slide, I’ve tried to come to pH 11,9 and added 19 ml of a 10% NaOH soloution
9. Reduce bromide to 5,5g/Ltr. as stated
10. Are there still questions, YES there are! What about Iodide and the infamous “inter image effect” ? look for
Dead Link Removed
this is a salvific Information !! Yellow-blue axis can be controlled with Iodide, as well as magenta – green axis is given by pH.


“ A very small quantity of potassium iodide is often included in the formulation to act as a restrainer, having greater effect on the top blue sensitive layer than on the other two layers. This means that the yellow dye content of the film can be controlled quite accurately by varying the iodide content (always assuming, of course, that you are mixing your own solutions from raw chemicals).”


RECEIPT I , base reciept
First Developer:
Tab Water ………………………...…….750 ml
Calgon………………………………………….. 2.0 g
Sodium sulphite, anhydrous ……………………28 g
Potassium carbonate, anhydrous ……………….14.0 g
Sodium bicarbonate …………………………… 12.0 g
Phenidone …………………………………….... 0.5 g (solve it in 10 ml of warm glycol)
Hydroquinonemonosulphate ……………………22 g (works well, perhaps less is possible)
Sodium bromide …………………………………2.6 g
Sodium thiocyanate………………………..…… 1.0 g
Sodium hydroxide 10% solution……………...25ml
Potassium iodide, 0.1 per cent solution ………. 4.5 ml
Water to 1.0 litre
pH 9,6


Color Developer:
Aqua demin……………………………...750ml
Calgon………………………………………2.0 g (not really necessary)
Trisodium phosphate crystals ……………. 36.0 g
Sodium hydroxide 10% solution ………..19 ml (!!)
Sodium sulphite, anhydrous …………….. 5.5 g
Sodium bromide ………………………….0.55 g
Potassium iodide 0.1 per cent solution ……40 ml (36 -37,5 seems to be optimal)
Sodium thiocyanate…………………………1.0 g
Citrazinic acid ………………………………0.6 g (!!)
CD3 ……………………………………… 10.5 g
Water to 1 litre
pH 11,9-12,1





Why do I work on this stuff?? I had a bunch of films showing me a severe magenta /magenta-Blue color cast, very bad… It seemd to be preaged, overheated, bad stored or whatever. It’s a kind of reversal engineering, the opposite of disposal…

To use this film I increased the pH of the CD as stated in the Jobo E-6 handbook, adding NAOH solution 10%. 4 ml/250/ml CD was to less, 6,5ml/250ml CD was too much The optimum additional amount was 5ml/250 ml (20ml/Ltr.) of the CD. The Red-Blue balance was neutral now.
There was still a slight blue cast. For solving that I added 2 later 3 mg potassiumiodide to the FD (+3mg /Ltr. was right)

That gave me following composition:

RECEIPT II

First Developer: for aged film (my Agfa's)
Tab Water ………………………...…….750 ml
Calgon………………………………………….. 2.0 g
Sodium sulphite, anhydrous ……………………28 g
Potassium carbonate, anhydrous ……………….14.0 g
Sodium bicarbonate …………………………… 12.0 g
Phenidone …………………………………….... 0.5 g (solve it in 10 ml of warm glycol)
Hydroquinonemonosulphate ……………………22 g
Sodium bromide …………………………………2.6 g
Sodium thiocyanate………………………..…… 1.0 g
Sodium hydroxide 10% solution……………...25ml
Potassium iodide, 0.1 per cent solution ………. 7.5 ml (Changed)
Water to 1.0 litre
pH 9,6



Color Developer:for aged film (my Agfa's)
Aqua demin……………………………...750ml
Calgon………………………………………2.0 g
Trisodium phosphate crystals ……………. 36.0 g
Sodium hydroxide 10% solution ………..49 ml (Changed)
Sodium sulphite, anhydrous …………….. 5.5 g
Sodium bromide ………………………….0.55 g
Potassium iodide 0.1 per cent solution ……36ml (Changed)
Sodium thiocyanate…………………………1.0 g
Citrazinic acid ………………………………0.6 g
CD3 ……………………………………… 10.5 g
Water to 1 litre
pH haven’t measured approx.12,5


Procedere:
Temp 38°C
Rotation, Speed 4 (Jobo CPP)

Temperated prewash 2 x 1 min ( this is important, I'v made bad experiencies with insufficient dry prewarm steps)

FD 6:45 min
Stop 1min
Rinse 4 min

Reversal exposure 2 x 2 min (1000 Watt Bulb)

Prewash 1 min
CD 5:00
Stop 1:00
Rinse 3 min
Bleach 8 min
Fix1 3min
Fix2 3 min
Final wash 10 min

Stabi 1 min


Here a lousy scan:

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First line : left Tetenal 3 bath , next added 6.5 ml Naoh sol.10%/250 ml to CD (reciept I), overcorrection leads to green shift
Second line : added 4 ml Naoh 10%/250ml CD (reciep I) still slight magenta cast. Next greyscale
Line 3 till 7
added 3 mg Kj to FD/ltr., added 5 ml Naoh 10%/250ml to CD (recieptI). This is reciept II, doesnt it look pretty ??


Measurements

Film Agfa precisa 100 @ 80Asa
Jobo test chart
Macbeth TR 527 “normal” Filter (Tolerance ?)

FD 6:45 min
CD 5:00 min.
.............|...R...|...G..|....B...|..R-G..|..B-G..
---------+-----+-----+------+------+-----+
Feld 3 ...|1,16..|1,11..|0,91..|0,05...|-0,2
---------+-----+-----+------+------+-----+
Feld 5 ...| 1,54 |1,51..|1,29..|0,03 ..|-0,22
---------+-----+-----+------+------+-----+
Dmax.....| 2,87 | 2,92 |2,82 |

Dmin 0,3 (through acetat sleeve)

Blue seems still ab bit underrepresented, but I do believe my eyes, the slides look very nice. Anyway the densitometer's filters mismatch and seems to be quite old... The Dmax is still a bit low, but acceptable for this film. It would be worth a try without citrazinic acid. Maybe bonzoetriazole in the FD is an option.





That’s not all, I’ve tested the Receipt I , my Base for modifications, on two up to date Kodak slide films (unmodified).

Anyway, this was all intended to develop aged film as well as possible. A cross check with Receipt No.I and fresh film showed very good potential, I'll try to show a scan, but be warned this is only a old flatbed scanner with deactivated light and a small light box to make it a cheap through light unit. Bad quality, but Trends are noticeabily..

[/URL][/IMG
1.Line Aged Agfa Film developed with Tetenal 3 bath Kit
2.Line Aged Agfa Film developed with my homebrew II (recieptII)
3.Line Greyscale
4.Line Kodak EPR64 developed in homebrew I (Base reciept, reciept I)
5.Line Kodak EPR64 developed in Tetenal (different light condition)
6.Line Kodak elitechrome 100 in homebrew I (Base reciept, reciept I)

The EPR64 and the Elitechrome 100, the both came out pretty well, The EPR64 is nearly perfect,just some fine tuning will left necessary. The Elitechrome100 seems to be quite warm and does have an increased contrast, but this seems to be normal for a “consumer film”.


Would be glad to hear some comments and suggestions !
Regards,
Stefan

 

[Mike Wilde]

Thanks for sharing

I have used the original formula, and agree that it isn't bang on, but never got around to further effort. Thank you for sharing you efforts, to send me in a better direction in the future.

 

[Rombo]

Excellent article!

I am developing slides by myself, with Jobo ATL 1000 and E6 3 bath kit. This article is really interesting, and I will try to make this chemistry by myself!

I have one question, if anyone can help. I found 3 boxes Agfa E6 (I think 44 process it is!), 6 bath. Boxes and bottles are still originaly closed and were stored in dark cold environment. They might be older than 5 years. Is there any chance to use these things without any major problems?

 

[Mike Wilde]

Agfa 44 old kits

watch out for the thiosulfate sulfuring out. Pour it into a separate jug before adding it to the mix. If there is sulfur on the bottom of the bottle, then look to the formula to make your own. The red bottle part of theblix is amm Ferri EDTA, and should still be good. The first developer might be off - llok to see how dark it has gotten. Experiment with a non-critical roll first. I used these up to 3 years out of date and they were ok.

 

[Rombo]

Agfa 44

Thank You for this information. I will do as You say.
Peter.

 

[esox]

What is Cd3 coponent ?

Hello,

What is CD3 component ?

Thanks

 

[Ian Grant]

Hello,

What is CD3 component ?

Thanks

It's the colour developing agent.

4-Amino-N-ethyl-N-(ß-methanesulphonamidoethyl-m-toluidine sesquisulphate monohydrate =
Mydochrome (May & Baker); Activol No 3 (Johnson), Colour Developer 3 (Merck); CD-3 (Kodak).

The chemical name can be written various ways.

Ian

 

[EdoNork]

You can use the CAS number of CD3 instead: 25646-71-3

 

[cinejerk]

Stefan you do some awesome work here !!!! Thanks Buddy

 

[feromarcin]

I haven´t Hydroquinonemonosulphate, it is dificult to obtain this in our country. Can I use Hydroquinone instead this? And how much? Thanks.

 

[cinejerk]

I think HQMS is difficult to find in any country, and expensive too !!

I have had some decent results using straight HQ. You use a lot less than HQMS. Probably around 6g per liter.

There are recipe's on this forum if you search.

 

[Rudeofus]

There are recipe's on this forum if you search.

I did not find the recipe on APUG, but here is a patent detailing the whole procedure for making HQMS.

 

[cinejerk]

There is some info here also: (there was a url link here which no longer exists)

 

[stefan4u]

Small update...

E6Homebrew update by request...

Quite a long time ago I posted a formulation for a bunch of outdated Films. However, here is a VERY GOOD working formulation for normal pictorial use. I have great success with Ektachrome100D, the movie film stock of E100VS, but still no scanner do demonstrate it…
A few notes in advance, my sequestering agent is still simple calgon, works perfect for me. In doubt I take aqua demin. for car accumulators. I do still use simple Phenidone A instead of Dimezone-S in the FD, works pretty perfect and is cheaper. Normally (the industrial way) the buffer capacy of the color developer is created by NaOH/KOH and phosphoric acid, I do replace them by the usage of the old fashioned Trisodiumphospate (dodecahydrate), NaOH sol.10% is used for pH correction only.
Needed / helpful Stuff: An accurate scale, pH meter, magnetic stirrer, some personal protection (goggles, gloves) some experience in homebrewing and some time…

First Developer:
Tab Water 750ml
Calgon 2g
Sodium-Sulfite 22,7g
Potash 14g
Sodium-Bikarbonate 12g
NaOH Sol. 10% 30ml
KBR 2,6g
Potassium Jodide 5mg (!) / 5ml of a 0.1%sol.
Potassium Thiocyanate 1g
Phenidon A 1g (solve it in 15 ml warm Diglycol/antifreeze)
Potassium-Hydroquinonemonosulfonate 22g

Fill up to 1Liter, pH 9,64 at 25°C
(the formulation is intended to reach this pH if your scale is accurate)


Color Developer:
Aqua demin 750ml
Calgon 2g
Trisodiumphospate (dodecahydrate) 36g
Sodium-Sulfite 4,5 g
NaOH Sol. 10% 35ml (this depends a bit on your preferences, maybe start with 28ml)
KBR 0,75g
Potassium Jodide 30mg (!)
Ethylendiamine (free base) 3ml
Citrazinic acid 1g
CD3 10,5g

Fill up to 1Liter, pH with 28 ml NaOH sol.10% is 11,96.

Anyway I do prefere a slightly higher pH, close over 12 with my Films and procedures, that’s why I take 35ml. “Formaly correct“ is a pH of 11.95 whith you reach with 28ml NaOH sol.10% in this formulation (if your scale is correct).


Stop 1
Citric acid 20g/Litre

Stop-Clear
Citric acid 20g
Sodiumbisulfite 20g

Bleach
A good preoxigenated C41 minilab bleach with prolonged time or a Homebrew bleach based on ferricyanide. Look out for E4 Bleach formulation

Fix, any neutral fix will work, I use a 2 stage fixation



Proceeding: Jacketbath temperature 38,4°C. Rotation „P“ at Jobo CPP2

3 x 30 sec. tempered prewash
6 min FD
2 min wash
2 min Stop 1
2 min wash
---------------
Reversal exposure
Film stays on translucent (!) reel, reels are transferred in the sink, covered by water. Reversal exposure with 1000W flood light, hold it and move it approx one feet over the reels. Do move the reels too. 2min from each side.
Do not splash around, take some care about the electric safety in your lab (IN ADVANCE!!)
-----------
Put the reels back in the drum and for tempering them again
3x 30sec. Prewash
5 min Color development
30 sec wash
2 min Stop-clear
2 min wash
10 min. bleach with preoxigenated C41 bleach, or 5 min. with Ferricyanide bleach
2-3 min wash
4 min Fix1
4 min Fix 2
10 min Final wash
-----------

1 min Stabi, with formaldehyde


„Milage“ at least 10 Films for a liter.
I do the first 6 Films in a Multitank 6 with 6:00 min FD time, using the whole liter. The following 4-5 Films in a second run for 6:15 min. Prior second use add 2 ml NaOH sol. 10% to the color developer to maintain pH. Partly used solutions keep for about 5 days, this is not very different from commercial stuff.

In spite of all you may need minor fine-tuning, simply because of weighting tolerances or slightly different workflow. So maybe you have to adopt the FD time in fractions or add a few ml NaOH / diluted sulfuric acid to get the color balance you desire. If doing so you will be surprised pleasantly.

Regards Stefan

 

[stefan4u]

Alternative “ZoneV” FD

Just for the records, an alternative FD based on the “ZoneV” formulation which ceased some time ago.

Tab water 750ml
Calgon 2g
Sodium-Sulfite 1g
Metol 2,5g
Sodium-Sulfite 21g
Potash 14g
Sodiumbicarbornate 12g
Hydroquinone 6g
Phenidon A 0,5g (solve in 15 ml warm Glycol)
Potassiumthiocyanate 1g
KBR 2g
Potassium-Jodide 10mg
NaOH Sol. 10%ig 20ml
Benzoetriazole 100mg

Fill up to 1000ml pH 9,65 at 25°C

This is for people who want to play around a bit with the E6 Homebrew Formulation, but do not have access to Hydroquinonemonosulfonate. I have to say clearly that the “real” HQMS formulation is better in meaning of contrast and correct color reproduction. But this one is not as bad, I`ve tested it too. A minor color crossover is visible, (very)slight green in the lower densities versus (very) slight magenta in the higher densities. The mid densities are neutral. The slides increase a pitch in contrast. But all in all this one works quite well together with my CD of the last posting…

Similar things I`ve noticed some time ago when adding Benzoetriazole to a FD based on HQMS, I would advise you to skip the benzoetriazole and increase the KBR to about 3 grams instead, to get rid /to minimize this color crossover, but it may not correctable completely.The latter is not tested jet, in opposite to my other formulations. Simply still have enough HQMS…

Unluckily a color crossover caused by uneven development thought the various emulsion layers can not be compensated by pH variations in the following CD.

Developers containing plain HQ are not very stable, under the presence of sulfite and oxygen in alkaline solution, HQ starts to convert to less active HQMS and changes the pH. If you want to have a constant result, brew it and use it within a constant time interval.


Regards stefan

 

[stefan4u]

Mmmm, I reactivated an old flatbed scanner on that win98 machine, this thing is so old, not even xp drivers are available… Internal light source is disconnected and a small light box shines through the slides.
Please keep in mind that the scanner quality is really bad, but you may get an idea…

Fist an Overview of various grey step wedges, the first 3 are HQMS based FD
Row 3 is my actual FD of posting No.14
Row 4 and 5 are modifications of the ZoneV FD
Row 6 is a test brew, converting HQ to HQMS, Wheatcroft patent (have to work that over some day…)
Row 7 again HQMS,



Grey steps actual brew


Crop of few pictures


Grey steps ZoneV



Grey steps converting HQ to HQMS




Once again, the scans are only a hint; the slides of my actual homebrew are delightful !

Regards stefan

 

[kb3lms]

Not too bad! Looks good. The problem of getting HQMS is what has always slowed me down with trying this myself.

Check out VueScan for your scanner. It just might support your old scanner. An XP driver would not necessarily be required.

http://hamrick.com/

 

[Bralors]

what is the formula of bleach you use? thanks!!

 

[Rudeofus]

what is the formula of bleach you use? thanks!!

From Stefan's posting on this very page:

Bleach
A good preoxigenated C41 minilab bleach with prolonged time or a Homebrew bleach based on ferricyanide. Look out for E4 Bleach formulation

Fix, any neutral fix will work, I use a 2 stage fixation

Note that E6 is not rated for C-41 and Ferricyanide bleach, but many seem to get good results. Fuji listed their E6 formulas in a patent, which is described (there was a url link here which no longer exists). You may not be able to get the 1-Thioglycerol for the prebleach, but you can replace it with Mercaptotriazole.

 

[Ben Hutcherson]

I realize I'm replying to a very old post, but still one with a lot of good information.

A little bit more recently I've been looking for some at-home options for E6, both for the commercial processing situation(always send-off around here, expensive, slow, and still not guaranteed to be good) and because I'd like to get into shooting sheet film again. I have an aversion to Blix chemistry, even though I used it the last time I did E6 at home, but prefer a proper 5-bath kit, and now from what I can see only Bellini makes home-sized kits.

I've spent the past few days researching recipes on and off, and given that I have almost everything on hand, would like to try with a non-critical roll.

With that said, is there any compelling reason why for this, or some of the other recipes out there, KSCN could not be substituted for NaSCN?(obviously adjusting amounts-per this recipe ~1.2g KSCN in place of 1.0g NaSCN). Most specify the latter, and I have the former on hand.

I'm trying to think through why this substitution wouldn't work, although at the same time I'm not totally clear on what role either serves. That aside, though, both should be completely dissociated, so the key with them would seem to be the SCN- ion. In most recipes I've looked at, both sodium and potassium ions are present in abundance. Removing 1g of NaSCN would remove only a minor amount of sodium relative to what the sodium sulfite in particular contributes(not to mention the other contributors). The additional potassium would be a bit more significant, but 1.2g KSCN would contribute ~.012mol K+ relative to the ~.20mol from potassium carbonate. I'm not sure if this would work.

I can always get the sodium salt, but I'm also working against a bit of a time constraint before Christmas shut-down at my lab space, and am hoping to do some of the developing at home during said break...

 

[Rudeofus]

With that said, is there any compelling reason why for this, or some of the other recipes out there, KSCN could not be substituted for NaSCN?(obviously adjusting amounts-per this recipe ~1.2g KSCN in place of 1.0g NaSCN). Most specify the latter, and I have the former on hand.

There is no reason, why one should not be able to use NaSCN, and I believe I have seen recipes doing just that. Where did you get this info from?

PS: I had some direct conversation with Stefan 10+ years ago, and he freely switched between Na and K.

 

[Ben Hutcherson]

There is no reason, why one should not be able to use NaSCN, and I believe I have seen recipes doing just that. Where did you get this info from?

PS: I had some direct conversation with Stefan 10+ years ago, and he freely switched between Na and K.

The recipes in the opening post of this thread all specify the sodium salt, hence my question.

I do see one posted in this thread on further reading that specifies the potassium salt, however it also states using the the same amount as the sodium salt(1g).

1.2g of the potassium salt would be the molar equivalent of 1g of sodium salt. So, if recipes in this thread use 1g of either the sodium or potassium salt, it's making me wonder how critical the amount of SCN- ion is.

As a more general question-with me freely admitting to complete ignorance of this-what role is the SCN- ion serving in this? It's something I've seen common in a lot of E6 first developers. I'll freely admit that even though I've mixed my own B&W developers as copies of commercial developers, I'm mostly familiar the "common" stuff(phenidone, metol, hydroquinone, etc as devs/reducing agents, sodium sulfite, borax, sodium carbonate etc, to raise the pH and some solvent effects on the grains, bromide or iodide salts to control contrast) but SCN- salts aren't in any of the developers I have in my own personal notebook. So, there again, it's a question more out of curiosity...

 

[Rudeofus]

The recipes in the opening post of this thread all specify the sodium salt, hence my question.

The sodium salt is more convenient, since it's a lot less hygroscopic than its potassium equivalent. I had an old stash of KSCN dissolving in the water it attracted from the surroundings. Sodium Thiocyanate also attracts water, but a lot less.

1.2g of the potassium salt would be the molar equivalent of 1g of sodium salt. So, if recipes in this thread use 1g of either the sodium or potassium salt, it's making me wonder how critical the amount of SCN- ion is.

As a more general question-with me freely admitting to complete ignorance of this-what role is the SCN- ion serving in this? It's something I've seen common in a lot of E6 first developers.

You can see thiocyanate as "minus bromide", i.e. the opposite of a restrainer. It raises activity and fog level of the developer. No, it does not "dissolve large grain". Since reversal FDs need to build up insane levels of contrast compared to even push development, they need all the activity you can get. To give you some impression, how active E-6 FD is:

• if you dilute E-6 FD 1:n, it will be n times slower to reach same contrast than E-6 FD standard working solution
• if you develop Tri-X with E-6 FD diluted 1:10 for 10 minutes at 26°C, you get normal contrast
• now imagine, what E-6 FD does to any photographic material after 6:15 @ 38°C.

E-6 FD is insanely active, and the thiocyanate is part of the reason why.

I'll freely admit that even though I've mixed my own B&W developers as copies of commercial developers, I'm mostly familiar the "common" stuff(phenidone, metol, hydroquinone, etc as devs/reducing agents, sodium sulfite, borax, sodium carbonate etc, to raise the pH and some solvent effects on the grains, bromide or iodide salts to control contrast) but SCN- salts aren't in any of the developers I have in my own personal notebook. So, there again, it's a question more out of curiosity...

There is a developer called DK-20, which contains 1g KSCN, so roughly half of what E-6 FD uses. It is - surprise surprise - a high contrast developer.

 

[lamerko]

There is a developer called DK-20, which contains 1g KSCN, so roughly half of what E-6 FD uses. It is - surprise surprise - a high contrast developer.

In fact, in most reversible black and white processes, the first (sometimes second) developer contains thiocyanate. The Kodak version - D-94 used sodium, which is normal - the entire formula is balanced with sodium. When things started to get trendy, they invented D-94a, which contains DTOD - a chemical that was called "evil" some time ago by a user from Egypt. The ORWO version in construction 4185 uses potassium thiocyanate - 6 grams per liter!