Liam Lawless' Enlarged Negatives by Reversal Processing?

[John W]

Does anyone know of a current way to get Liam Lawless' article Enlarged Negatives by Reversal Processing? The original version of the article was in The World Journal of Post-Factory Photography #2, but the email address for Judy Seigel to obtain back issues no longer exists (domain is gone). The updated version from http://rmp.opusis.com/documents/reversal4.pdf is gone as well, nor is it available via archive.org.

Liam appears to have had a website at Dead Link Removed at one time, but that's gone as well.

 

[payral]

Did you tried to get it back from there:
http://www.archive.org/web/web.php

 

[Lukas Werth]

I think I do have a downloaded pdf still somewhere on my hard-disk at home. Give me some time, I will attach it.

However, I am using this process regularly, and I would recommend quite some alterations of Liam's original instructions. I think I have made notes about this somewhere on Apug not too long ago.

 

[dancqu]

Does anyone know of a current way to get Liam Lawless' article
Enlarged Negatives by Reversal Processing?

Check at www.unblinkingeye.com . Just checked.
I was sure the article WAS there. I've read the article at
that site. Odd it's gone. Liam has a few other articles
there. I'll miss it. Dan

 

[BobNewYork]

I think this is is: http://unblinkingeye.com/Articles/NbyR/nbyr.html

Bob H

 

[Jon King]

There were updates, mainly simplifications to his process in The World Journal of Post-Factory Photography #3 and #4. Judy Seigel is active on the alt-process-photo list.

 

[John W]

Did you tried to get it back from there:
http://www.archive.org/web/web.php

Yep, that was one of the first things I tried as I mentioned in my original post. Thanks for the thought, tho!

 

[John W]

However, I am using this process regularly, and I would recommend quite some alterations of Liam's original instructions. I think I have made notes about this somewhere on Apug not too long ago.

Thanks for looking for the article, Lukas. I'll search APUG for your process notes.

 

[dancqu]

I think this is is:
http://unblinkingeye.com/Articles/NbyR/nbyr.html Bob H

Yes that's the article; Less is More. I take it as being Ed's take
on Liam's method. I'd say a good second source. Dan

 

[yellowcat]

A few years ago I made a number of enlarged negatives for a client who wished to use them for making cyanotype prints.
I printed the negatives onto Ilfochrome ohp film and with a little experimenting was able to get good results. My client was very happy with the enlarged negatives.

 

[payral]

I checked my hardrive and found the Liam's file.
So here it is attached. I hope it will help

 

[dancqu]

I checked my hardrive and found the Liam's file.
So here it is attached. I hope it will help

Is there some reason potassium ferricyanide would
not work? Also, would not sodium bisulfate work? It
is a suggested substitute for sulfuric acid. Dan

 

[John W]

Dan, there are several classes of silver photographic bleaches, with different actions on the silver in the film. (**) For a reversal process, a bleach is needed that converts the exposed silver to a form that is soluble in the bleach. For potassium dichromate + sulfuric acid, the silver is oxidized to silver sulfate.

So in the reversal processing sequence, we have:
1) Unexposed film, no image -- unexposed silver halogen salts.
2) Exposed film, latent image -- exposed and unexposed silver salts.
3) Developed film, silver positive image -- metallic silver and unexposed silver salts.

In normal processing, we'd fix now, removing the unexposed silver salts, leaving behind only a metallic silver image. Reversal, however, continues on like so:

4) Bleached film, metallic silver removed -- unexposed silver salts.
5) Washing and clearing
6) Reexposure, latent image -- exposed silver salts.
7) Redevelopment, silver negative image -- metallic silver.
8) Washing
9) (optional) Hardening

Potassium ferricyanide is used as a re-halogenating bleach, where the silver is converted back to a halogen form (e.g. with bromide to achieve Ag -> AgBr), which must then be removed by fixing. This creates a problem during steps 6 and 7 above, since the silver salts from the bleaching would result in nasty image fog.

(**) I'm going from memory on the bleach info, hopefully someone will correct if I've misstated anything. Mean library D) took back Mason's Photographic Processing Chemistry, and my copy of Haist's Modern Photographic Processing hasn't arrived yet.

 

[dancqu]

For potassium dichromate + sulfuric acid, the silver is
oxidized to silver sulfate.
Potassium ferricyanide is used as a re-halogenating bleach,

...hopefully someone will correct if I've misstated anything.

I mentioned only potassium ferricyanide. No mention of
re-halogenation was made. Likely ferricyanide is not used
because silver ferrocyanide is highly insoluble while silver
sulfate is very slightly soluble.

After posing the question I pondered some. So the
reversal process produces silver sulfate. Dan

 

[John W]

I mentioned only potassium ferricyanide.

Right; I'm rather new to photographic chemistry, so I kind of ran off with the common use of potassium ferricyanide as in the formulation for sepia toner... blasting right past using it alone as a bleach. I note that this article on blue toning by Liam Lawless confirms that the silver ferrocyanide can be removed by fixing, something I'd only just assumed earlier.

 

[ghost]

pot ferri IS a re-halogenating bleach- a completely different type of chemical action than what is needed for this process- that's what he was trying to explain to you my man-

 

[dancqu]

I note that
this article on blue toning by Liam Lawless confirms that the
silver ferrocyanide can be removed by fixing, something I'd only
just assumed earlier.

You've made clear the two bleach methods. Bleaching for removal
of the silver image does call for the silver's conversion to a soluble
form. Checking for solubilities I find the permanganate to be
9 grams per liter and the sulfate 8.3 grams.

A post fix image bleaching with potassium ferricyanide ALONE
leaves an image of silver ferrocyanide. Following toner or
redevelopment results will likely differ from those of a
halogenated image. I'm going to check on that. Dan