RE: Reversal processing for enlarged negatives (was Re: RES: The Great Scanner debate - round one)

From: Loris Medici ^lt;loris_medici@yahoo.com>
Date: 03/23/04-07:38:52 AM Z
Message-id: <006801c410dc$30e1f220$ce02500a@altinyildiz.boyner>

Hi Ryuji thanks for the detailed answer...

> -----Original Message-----
> From: Ryuji Suzuki [mailto:rs@silvergrain.org]
> Sent: Tuesday, March 23, 2004 10:08 AM
> To: alt-photo-process-l@sask.usask.ca; loris_medici@yahoo.com
> Subject: Reversal processing for enlarged negatives (was Re:
> RES: The Great Scanner debate - round one)
>
> ...
>
> > Ryuji, the 24" x 30' roll of orto-litho film that I
> > had ordered just arrived to the store. They will cut
> > it to 20"x25" sheets for me - will have ~ 300 sheets.
>
> Why do you waste 4cm at the end? Maybe this is just me, but
> I'd rather keep that margin and don't use it, so that the
> risk of damage to the image area is reduced. (Also I might
> want to cut it into squares since I love square images.)

Sorry, I have stated wrong dimensions (twice!) - guess I was very sleepy
last night. The exact dimensions are 50cm x 30m (20" x 100') and I
finally decided to have it cutted to 25cm x 30cm size (10" x 12", I just
ordered an 11" x 14" contact print frame from B&S) - this will make ~
200 sheets with no waste at all.

> For the first developer, I'd suggest to use some of the cold
> tone developers, but the classic choice would be D-19 with
> 2g/L or so of potassium thiocyanate. Ilford ID-62 (is
>
> ...
>
> dozen developers published for reversal processing. Since you
> don't care about the speed of the reversal processed film, I
> think D-19 plus thiocyanate is pretty close to optimum.

Ok, you say that D19 formula + 2g/L potassium thiocyanate is good for
optimum first development. Then what should be the development time?
Should I use this developer in stock strenght? BTW Is the formula
metioned @
/lists/alt-photo-process/2001/aug01/msg00424.html Ok?
(Elon is Metol I presume...)

> ...
>
> When you flash the film, it may or may not be helpful to
> flash both front and back sides with diffuse light. If the
> film has dense base or good antihalation dye, back exposure
> would require much longer time. I think the APH Lith film had

I didn't understand this... 1) Why should I want to flash from the back
side? 2) What if I use light from an enlarger with condenser head?

> ...
>
> They recommend water rinse and fresh plain acetic acid bath
> to reduce pinhole and halt development. Unless you like to do
> extra work, I recommend to use buffered acetic acid stop
> bath. If the bath is buffered in the range 4.5 to 5.5,
> pinhole shouldn't be a problem. This type of bath has a large
> processing capacity and arrests development very rapidly.
> Sprint stop bath (forgot name... was it BLOCK or something?)
> is such a product.

Well, I have only access to standard Ilford Ilfostop or Kodak Indicator
Stop Bath (both w/indicator dye). What would be your comments for these?

> I'd bleach in safelight.

I bleached lights on in all my previous trials. (the Lawless / Buffaloe
articles say that one can turn the lights after the film is in the stop
bath for at least 30 secs. What negative effect will/may produce if I
bleach lights on?

> ...
> They redevelop in developer with light on, but for enlarged
> negative purposes, I'd recommend to use Kodak rapid selenium
> toner if you prefer higher Dmax, or the toner part of sepia
> toner (either sodium sulfide or alkaline thiourea works, but
> you can use Kodak brown toner, or a couple of soybean size
> piece of liver of sulfur in a liter of water works as well.)
> if you prefer lower Dmax, both with or without room light.

I also didn't understand this - using toners as second developers? You
say if I "develop" - in safelight conditions - in Selenium or Sepia
toner then I don't need to re-expose the bleached film? What should be
the dilution for Kodak Rapid Selenium Toner? I have powder thiourea, how
I can make "alkaline thiourea" toner using it? What would be the
"development" timing for each toner?

> ...
>
> Anyway, the first developer, the way you flash expose the
> film, and the way you redevelop are three major things I'd do
> differently from that article.

Thanks again, I don't know much about silver chemistry (or any other
type of chemistry) but your message was very informative, I'm sure it
will guide me to many sites on subject and make me learn better the
mechanism of silver imaging... But you have to elaborate some more
detail because I got confused ;)

> > The sulfite is old (around 1 year) and
> > was in a plastic bag (knotted mouth) - do you think it
> > is still good? I remember it gets bad very quickly so
> > what else I can use to clear the film?...
>
> Sodium sulfite in dry form is stable, though once you
> dissolve in water, I is just like developer solution and
> won't last long.

Ok, it seems that I've confused it with sodium bisulfite. I had read
this: http://silvergrain.org/Photo-Tech/chemistry-misnomers.html once
looking for other information and that caused my confusion (my fault).

Regards,
Loris.
Received on Tue Mar 23 07:34:32 2004

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