I want to agree with what someone else (I've lost track of who!)
suggested: what the original poster is seeing is an artifact of the
scanning software. I've seen this myself when scanning color negatives.
My flatbed scanner can scan two strips of negatives. It will try to pick
the best overall filtration for the entire strips. If one negative is
off exposure by a bit, the filtration will go all wonky. Even if I
select individual frames for scanning, if the exposure is off, it can
have trouble with the color. That's why I'm going to be spending the
next couple days in the darkroom instead of on the computer!
Ken Hart
kwhart1@xxxxxxxxxxxxxxx
On 10/25/21 11:01 AM, `Richard Knoppow wrote:
The yellow mask is in all color negative materials. Its purpose is to correct for spurious transmission of certain of the dyes that make up the image. The built-in mask was invented by a fellow at Kodak (you know I have trouble with names). In this process the dyes are colored to begin with and the color is changed in proportion to the development. If you examine a color negative through a magnifier you will see that the mask disappears where certain colors appear, thus, there is what amounts to a positive mask image along with the negative printing image. The colored dye mask results in an amber color to unexposed parts of the film. I don't think that is what is being seen here because it is consistent in all parts of the film.=============================================================================================================
On 10/25/2021 7:15 AM, BOB KISS (bobkiss) wrote:
DEAR RICHARD,
Perhaps I am missing something obvious but do I recall correctly that color C-41 negatives all have that yellowish/orange cast to make printing easier, requiring less filtration?Kodak referred to it as "the mask".I only used C-41 black and white film once (because I hated the results) so I don't recall if it had the same overall cast.
CHEERS!
BOB
-----Original Message-----
From: pure-silver-bounce@xxxxxxxxxxxxx [mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of `Richard Knoppow
Sent: Sunday, October 24, 2021 8:59 PM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: Yellow colouration in C-41 negatives
Is the yellow all over the negative, I mean up to the edges
rather than just the image area? I am looking for clues. Can you
tell if its on the emulsion side or the support side? The
question is whether its actually some sort of flare. Old
Kodachrome slides and prints often had a yellow color from the
lacquer on them. Two kinds of lacquer, one came off with a mild
alkaline solution like print developer, the other with a solvent
but I don't remember what. I think that is unlikely here because
it would be all over the film.
Is this color or stain uniform?
On 10/24/2021 1:01 PM, Richard Urmonas wrote:
> While not strictly silver I was hoping someone could shed some
> light on a yellow colouration on C-41 negatives. I "inherited"
> the negatives from a family member so I do not know the history
> of development and storage, but expect these were processed by
> a local 1 hour lab and then stored in a drawer for a number of
> years. From the contents I think these date from the 1990s.
> The issue I am observing is a yellow colouration across the
> whole frame, like a yellow filter was used. This seems to have
> happened on random frames and can affect a single frame to 3 or
> 4 in a row but then have "good" frames. There is even a case
> where 2 frames apparently taken a short while apart have one
> with the yellow colouration and the other looking fine. Note
> that the yellow colour is on the positive image from my
> scanner. The colour shift can be seen on the negative. This
> only affects some films, others which have been stored together
> with the affected films show no issue. I would have suspected
> some colour fading effects, but this does not explain the whole
> frame being affected. Can anyone shed some light on what might
> be going on?
>
> Thank you,
>
> Richard Urmonas
>
>
> =============================================================================================================
>
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--
Richard Knoppow
dickburk@xxxxxxxxxxxxx
WB6KBL
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