Kodak E-7 process

[bnxvs]

Sometimes there are references to the Kodak E-7 process as a simplified version of E-6. Unfortunately, I do not know anyone who really held (read) the "Manual for Processing Kodak EKTACHROME Films using E-7". Does anyone know how the process E-7 actually differs from the standard E-6? Or maybe someone has this manual? Why is there such a secret around this process?

 

[foc]

Is this the reference you are talking about?
E-7 is the "mix-it-yourself" version of E-6. Functionally it was equivalent, but there were a few differences.
From Wikipedia https://en.wikipedia.org/wiki/Ektachrome
I have never heard of Process E7 and I don't understand the "mix it youtself".
All photo chemicals come in either a liquid or power from the main manufacturers and you then follow their mixing instructions.That to me is mix it yourself.
If you mix raw chemicals then you follow a certain formula so I don't see where E7 would come from E6.

Maybe E7 is simular to the grassy knoll or bigfoot.

 

[Rudeofus]

A while back Grant Haist published a formula close to C-41, called C-42. There is a non-trivial chance, that a similar home brew formula was put forward for E-6, suitable named E-7. I have not seen these formulas, and recommend people try Stefan Lange's homebrew/chromebrew formulas, since these are public, they work well, and they can be mixed from ingredients available to photo amateurs.

 

[bnxvs]

[0047]
Thus, in a preferred embodiment the present invention is used with the well known, widely employed E-6 color reversal development process described in the Eastman Kodak Company publication, Manual for Processing Kodak EKTACHROME Films using E-7 (1980), or a substantially equivalent process.

https://patents.google.com/patent/EP0547983A1

This invention is preferably employed to determine the bromide ion content in a developer solution which is used in the production of images from silver halide based color reversal or color negative materials. In one embodiment, it is preferred that the developer solution be the first developer, i.e., the non-chromogenic developer employed in the E-6 process described in Manual for Processing Kodak EKTACHROME Films using E-7 (1980) Eastman Kodak Company, Rochester, N.Y.

https://patents.google.com/patent/US5212098A/en

etc...

 

[fdonadio]

They look like typos for me.

These patents were originally filed in the 90’s, when computers were already widely used. Maybe the text in one of the patents was copied and pasted from the other.

Since process E-6 was released in 1976, I believe (it’s my opinion) that 1980 would be too soon for a new process.

Cheers,
Flavio

 

[mshchem]

What's the real content of the call with the Ukrainian leader? Fuji and Kodak have a secret program to co-produce Instax/Instamatic Ektachrome Super Slides in the old Kiev 88 factory. 127 is the new forty.

 

[MattKing]

See page 3 of this document for a Kodak reference to process E-7: https://www.kodakalaris.com/getmedi...ssing-Products-KES110_May-2009_FINAL.pdf.aspx

 

[cmacd123]

I vaguely recall a reference that e-7 was a process for large volume labs to use under license from Kodak. It might well be "mix it yourself" for a lab who would have at least a chemistry expert on staff. recall that some folks buy Metol in 205l drums.

 

[BradS]

I think Sasquatch is taking a vacation.....likely in southwestern Oregon...and he’s using the alias, ‘Bigfoot’.

 

[bnxvs]

The Kodak E-7 process, if I understood correctly, was designed as a simplified alternative to the E-6 process, for home use. Similar to process E-4, which was an alternative to process E-3.

 

[foc]

The Kodak E-7 process, if I understood correctly, was designed as a simplified alternative to the E-6 process, for home use. Similar to process E-4, which was an alternative to process E-3.

E4 process was different to E3 in that E4 used a reversal agent (IIRC highly toxic) and ran at a higher temp.
Again as far as I can remember you could process an E4 film in E3 chemicals and using the light reversal method instead of the reversal agent.

I am sure someone with better knowledge of reversal processing than myself could give better details.

There is one person that would know all, Photo Engineer

 

[AgX]

See page 3 of this document for a Kodak reference to process E-7: https://www.kodakalaris.com/getmedi...ssing-Products-KES110_May-2009_FINAL.pdf.aspx

The E-7 reference only hints at the stabilizer.

From this I conclude that E-7 is the washless variant of E-6.

 

[fdonadio]

See page 3 of this document for a Kodak reference to process E-7: https://www.kodakalaris.com/getmedi...ssing-Products-KES110_May-2009_FINAL.pdf.aspx

That’s enough proof for me. Now, why didn’t anyone get to hear about this E-7 process?

 

[Anon Ymous]

The E-7 reference only hints at the stabilizer.

From this I conclude that E-7 is the washless variant of E-6.

I'm not entirely sure. E6 used to have a stabiliser bath that contained formaldehyde. This was replaced by a prebleach bath that contained a bleach accelerator, as well as a formaldehyde - bisulfite adduct. It reduces the exposure to formaldehyde to personel, but is also effective at stabilising the dyes that E6 uses, that require formaldehyde. Nowadays a final rinse is used that uses a biocide and wetting agent.

 

[AgX]

I know, but that would just be a product development, without any processing variation, but not a basically different process as a washless one would be. So there would not ne a reason to give the process a different designation.

Though I then would have chosen E-6WL or such instead of E-7....

 

[Mr Bill]

Does anyone know how the process E-7 actually differs from the standard E-6? Or maybe someone has this manual? Why is there such a secret around this process?

Let me first say that I have no personal knowledge of an E-7 process, but am not surprised about its (presumed) existence.

The reason it is generally unknown, assuming it exists, is most likely that the information in it is confidential and proprietary. Cmacd123 is most likely correct. The only people (outside of the manufacturer) who would have first-hand knowledge about it would be licensed holders of the formulary manuals. And they apparently have done a good job of maintaining the confidentiality.

I mentioned a similar situation with the case of the C-42 process. See my post #19 in this thread:
https://www.photrio.com/forum/threads/c-42-is-kodaks-home-version-of-c-41.89135/#post-1191803

I would never have mentioned anything about C-42 except that certain aspects have previously been publicly revealed. One is that Haist of Kodak had published a C-42 developer (tank solution) formula (per Rudeofus in this thread); a second is that a former Kodak guy had once mentioned on a forum that such license agreements were sometimes made with large finishers. So there was already some public knowledge of C-42. I'm not gonna say more, but people should be aware that the ideas that C-42 was intended for "home use" and that it is somehow not equivalent to C-41 are only speculation.

Ps, some patents listed in this thread refer to an E-7 processing manual. One might presume that such manuals are therefore open to the public, but I don't think that this is correct. Perhaps they might be used in court cases, but presumably could still be held in confidence. I'm just speculating about this, though; I'm sure that a patent attorney could answer this.

 

[AgX]

If it was a "complete" process, in the Kodak waste handling listing above the other parts aside of the stabilizer would show up too.

 

[Terrence Brennan]

I worked for a larger photofinisher in the 1980s, and we used 3rd party chemistry kits for process C-41 and E-6. We did some bulk mixing, and also had the manuals for C-42 and E-7, which I was told were the bulk mix equivalents of C-41 and E-6. We found that the 3rd party kits were cheaper and faster and less problematic that bulk mixing.

 

[AgX]

https://patents.google.com/patent/EP0547983A1


https://patents.google.com/patent/US5212098A/en

etc...

In that context "E-7" obviously is a typo.

 

[AgX]

I worked for a larger photofinisher in the 1980s, and we used 3rd party chemistry kits for process C-41 and E-6. We did some bulk mixing, and also had the manuals for C-42 and E-7, which I was told were the bulk mix equivalents of C-41 and E-6. We found that the 3rd party kits were cheaper and faster and less problematic that bulk mixing.

This is in contradiction to the document from post #7.

 

[MattKing]

This is in contradiction to the document from post #7.

Not necessarily. The E7 stabilizer may be the only E7 component that differs from E6 for the purpose of that document.

 

[AgX]

Exactly. That was my idea uttered in post #12. But Terence hints a E-7 being a made from scrap or so process. Then either all or none chemical would show up at a disposal list.

 

[MattKing]

If E-7 was essentially the "mix from scratch components because you are using it it volume lab quantities" version of E-6, it may be that the disposal rules for the E-7 components are just the E-6 rules, save and except for the E-7 stabilizer.
That stabilizer may include formaldehyde, which differs from E-6, where the formaldehyde like component is included in an earlier stage of the process. The inclusion of formaldehyde would be a logical reason to have special disposal rules for that E-7 component.

 

[cmacd123]

If E-7 was essentially the "mix from scratch components because you are using it it volume lab quantities" version of E-6, it may be that the disposal rules for the E-7 components are just the E-6 rules, save and except for the E-7 stabilizer.

Or perhaps there was no advantage in mixing the stabilizer from scratch, (it tends to be one of the least expensive solutions in most processes) and so Kodak sugested just sticking to the one for E6. recall the KES pub refers to KODAK Stabilizer and Replenisher E-6, E-7 and E-6AR (Working solution) so it would be the same product in all three cases.

 

[Terrence Brennan]

The lab I worked for mixed a house stabilizer for use with all of our film processes, except C-41A, the Disc film process, and our B&W film processor, which was simply Photo-Flo and water. The film processes which used the house stabilizer were C-41, E-6, E-4 and the old Ektachrome movie film process, which was EM-26 if I remember properly (and I may not!).

The house stabilizer for most of our processes was mixed in 600-gallon batches, and was mostly water, with a 1-gallon bottle of Photo-Flo 600 added and a quantity of formaldehyde. AFAIR, the stabilizer for C-41A was water, formaldehyde and a wetting agent called, if I remember correctly, "NO-STAT-X" instead of the Photo-Flo.

After all these years, a discussion on stabilizer. Who would've thunk it!