Base colour of cross processed film? Fuji RAP/Astia 100

I know I shouldn't have an orange base but what should the colour
be? Greyish? Or clear?

Thanks
Nick

 

Assuming this is an E-6 film cross processed in C-41, you should have
the same clear base in unexposed areas that you'd have in fully burned
out areas (like the 35 mm leader) as a positive transparency. Only B&W
films have a gray base (which, I'm informed by someone who should know,
is still a color in the anti-curl back coating or underneath the
emulsion, not in the plastic material of the film base itself).
Overall, though, base color is determined by the film type, not by the
process.

--
I may be a scwewy wabbit, but I'm not going to Alcatwaz!
-- E. J. Fudd, 1954

Donald Qualls, aka The Silent Observer
Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm
Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

 

Well all of mine have come out with a yellowish base. Maybe with a hint of
brown.
Have you tried cross-processing that Astia yet?

Simon.

 

The very end of the leader is bluish and I guess the

Yes, you might get some sort of tint if you don't use a stop bath between the
dev and bleach. Normal C-41 doesn't call for this but several Kodak pubs
indicate a tinted base might happen without the stop on print film. That most
likely goes for chrome film processed in C-41 also.

Larry

 

Ya this morning. The film is drying. It's fairly clear but if you put a
gun to my head I'd call it grey. It's not like frosted glass but it's not
perfectly clear either. The very end of the leader is bluish and I guess the
grey really has a mild blue tint to it.

Nick

 

I was expecting perfectly clear base but it's not. The negatives seem good
will see how they print.

Nick

 

Hmm... this is interesting. I use a stop bath.
I also use a pre-wash of warm water to get the film up to the right C-41
temperature. When I pour the pre-wash away it's VERY blue... (I'm talking
about cross-processing Astia here).

Simon.

 

I didn't do a pre-wash. The exposed leader is deeply blue. Kind of nice in
a way. Without the orange mask I'm not sure how to judge the negative
colours but if it wasn't cross processed they'd look right.

With me the film is putting out enough dye to make the stop change
colour. So not only does it turn the developer but the stop is orange also.
It's mostly C-41 film in the tank.

Nick

 

It would make more sense if you process yourself to use E-6 color
developer and simply skip the first developer and reversal bath steps.
After all, E-6 color developer is going to be more suited to E-6
films.

 

The gray in 35mm film is NOT an anti halation coating.
Rather it is a pigment in the support itself. Both back
coating and under emulsion coatings are used for
anti-halation purposes, the latter in most color films.
These are decolorized by the sulfite in either developer or
fixing bath. No color film uses a back coating other than
the Rem-Jet coating used on Kodachrome and some older motion
picture stocks.
You can prove this easily by soaking some film in
household bleach. This will completely remove all the
gelatin from both sides of the film leaving only the
support.
The orange color in color negative film is not the
support or a coating but rather the color couplers (dye
formers). They are colored when in the unreacted state to
provide an automatic color mask to correct the parasitic
transmission of the dye. In effect they raise the minimum
density. Usually, colored couplers exist in two layers of
the emulsion. The coupler in image areas is converted to the
appropriate color for that layer. A careful examination of
the image under high magnification will show that the "base
color" does not exist in highly colored portions of the
image. The idea of using colored couplers for masking
originated with Westly T. Hanson of the Kodak Research
Laboratory sometime in the mid 1940's. Kodak's first
chromogenic negative film, Kodacolor, did not have the
couplers, it was introduced in a later version of Kodacolor
and in Ektacolor.
There is no way of removing the mask without also
removing the dye image.
This method of masking is never used on color reversal
films, nor is anti-light-piping pigment in the support. All
should have perfectly clear supports after processing.

 

It would make more sense if you process yourself to use E-6 color

I don't think this will work. The color developer I think is a fog type
developer. Everything will have a fog if it works at all.

Larry

 

Define "cross processed." If you processed the film in B&W chemistry,
you won't have bleached away the colloidal silver yellow filter layer
(which normally protects the green- and red-sensitive layers from blue
light exposure in the camera). If you processed in C-41, the bleach-fix
or bleach step that removes the image silver should have also removed
that filter layer.

So, what color did you wind up with? C-41 films, of course, have the
orange base, but that's the base color (i.e. it's under the emulsion and
antihalation, or in the back coating, and designed not to wash out);
slide films generally have a fully clear base.

--
I may be a scwewy wabbit, but I'm not going to Alcatwaz!
-- E. J. Fudd, 1954

Donald Qualls, aka The Silent Observer
Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm
Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

 

You and Rowland Mowrey need to compare notes, so we can all get the same
story. I just had it from Mowrey on photo.net (like literally a few
days ago) that the gray color of B&W films is in the undercoating or
back coating, not in the support; he claimed to have handled hundreds of
samples of support material and all was completely clear.

The way you tell it is the way I had understood it, too -- but in direct
opposition to Mowrey's tale, and with his background, I have to give him
some credibility. Perhaps the support is dyed before coating, but at a
later stage than where he handled the samples...

In any case, we all seem in agreement that no E-6 film should have a
residual pigment, dye, or any other sort of color in areas that were
either grossly overexposed (for normal reversal positives) or completely
unexposed (when cross-processed in C-41). I'd be interested in what
Nick has...

--
I may be a scwewy wabbit, but I'm not going to Alcatwaz!
-- E. J. Fudd, 1954

Donald Qualls, aka The Silent Observer
Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm
Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

 

I think you mean to skip the first dev and *bleach* steps -- if you skip
both developers, you'll get clear film base after the fix.

--
I may be a scwewy wabbit, but I'm not going to Alcatwaz!
-- E. J. Fudd, 1954

Donald Qualls, aka The Silent Observer
Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm
Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

 

Worse than that I think. It will make all the halide developable so
the film will come out black. If you bleach out the silver it will
still be black since all the coupler will have been converted to dye.
Remember that the dye is produced by a reaction of the coupler with
developer reaction products.

Richard Knoppow
Los Angeles, CA, USA

 

I glanced at a formula for the 1st E-6 developer. It looks like a B&W
developer.

Nick

 

E-6 film in C-41 chemicals.

Nick

 

I glanced at a formula for the 1st E-6 developer. It looks like a B&W

CORRECT

Larry

 

The negatives are very grainy. Reminds me of 1980's 400 speed film but
worse. OTOH the prints don't look that grainy. It sort of blends in. By
chance the colour filtration came in at the intial starting point for the
paper so I didn't have to waste any time getting that right.

Nick

 

No, the orange color is the leftover color couplers (I think they are
colorless on at least one of the layers) and act as a built in correction
mask. Where the coupler forms a color there is no masking (for that layer) and
where there is no color formed the leftover coupler leaves a color residue.

Bert