Re: daft question : diagnosis of magenta cast for c41

"Rachel Koktava" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) om...
> Hi all,
>
> this seems a really daft question but when people (on this
news group)
> state that their negatives have a magenta cast do they
mean magenata
> to the naked eye, or after the image has been made
positive?
>
> I'm systematically experiencing a cast on images that I've
developed
> at home and scanned using a photoscanner. THe resulting
positive image
> has a slight magenata cast.
>
> I found information on this newsgroup stating that a
magenta cast is
> under-developing, and a green cast over developing - but
are they
> talking about the actual negative or the positive image
that results.
>
> Other possibilities are incorrect ph in the developer or
contamination
> of the chemicals, or insufficient bleach/fix.
>
> Any help appreciated
> regards
> Rachel

I don't know what others mean. Since color negatives can
be corrected to a fairly large degree in printing the color
"cast" is probably in comparison with a standard negative.
Color shift is probably a more accurate term.
Because you are scanning the shift could be coming from
the scanner or scanning process in some way. Some scanners
which work well with transparencies do not do so well with
color negatives. For one thing, transparencies do not have
the color masking dyes, which give color negatives their
overall yellowish orange color. These dyes exist on two of
the thee film layers, their purpose is to correct for the
less than perfect absorption of the dyes in those layers.
When they work right the result is better color purity and
saturation. It may be that your scanner is not doing a good
job of compensating for these dyes.
One suggestion is to borrow, if possible, a good color
negative from someone else and test scan it. By a good
negative I mean one from which excellent standard color
prints have been made. See what it looks like when you scan
it. If it shows the same magenta shift the problem is NOT
with your negatives and you can approach it as a scanner or
software problem. If the test negative does NOT show the
same shift then look at your processing to find what may be
happening. I think Kodak has a data sheet on their web site
showing common problems with color processing. There are
also several experienced color film processors on this
group. I am surprized one of them hasn't responded by now.

--

---
Richard Knoppow
Los Angeles, CA, USA
(E-Mail Removed)




Richard Knoppow

Sorry, I meant to answer that one it slipped through the
cracks the other day. You however have answered the question very
completely :-) Once again!!!


In article <beohln$jas$(E-Mail Removed)>, "Richard Knoppow" <(E-Mail Removed)> wrote:
>
> I don't know what others mean. Since color negatives can
> be corrected to a fairly large degree in printing the color
> "cast" is probably in comparison with a standard negative.
> Color shift is probably a more accurate term.
> Because you are scanning the shift could be coming from
> the scanner or scanning process in some way. Some scanners
> which work well with transparencies do not do so well with
> color negatives. For one thing, transparencies do not have
> the color masking dyes, which give color negatives their
> overall yellowish orange color. These dyes exist on two of
> the thee film layers, their purpose is to correct for the
> less than perfect absorption of the dyes in those layers.
> When they work right the result is better color purity and
> saturation. It may be that your scanner is not doing a good
> job of compensating for these dyes.
> One suggestion is to borrow, if possible, a good color
> negative from someone else and test scan it. By a good
> negative I mean one from which excellent standard color
> prints have been made. See what it looks like when you scan
> it. If it shows the same magenta shift the problem is NOT
> with your negatives and you can approach it as a scanner or
> software problem. If the test negative does NOT show the
> same shift then look at your processing to find what may be
> happening. I think Kodak has a data sheet on their web site
> showing common problems with color processing. There are
> also several experienced color film processors on this
> group. I am surprized one of them hasn't responded by now.
>
> --
>
> ---
> Richard Knoppow
> Los Angeles, CA, USA
> (E-Mail Removed)

--
Check out My Homepage at
http://members.bellatlantic.net/~gblank

Support bacteria - they're the only culture
some people have." -Stephen Wright