A Photography forum. PhotoBanter.com

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » PhotoBanter.com forum » General Photography » Film & Labs
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

c-41 color shift



 
 
Thread Tools Display Modes
  #1  
Old December 6th 05, 05:22 PM posted to rec.photo.film+labs
external usenet poster
 
Posts: n/a
Default c-41 color shift

It's been over twenty years since I worked in a lab so...

I've had some film developed at a local Costco a couple times in the last
years (don't bother telling me I get what I pay for) I've noticed that the
film they develop shifts blue when it's printed, even when it's printed at
a different lab. I suspect that they are skimping on some replenishment,
for all I know they don't even run controls. Any thoughts on what could
cause a blue shift with c-41 chemistry?

Paul
  #2  
Old December 12th 05, 02:36 AM posted to rec.photo.film+labs
external usenet poster
 
Posts: n/a
Default c-41 color shift

Pdigmking wrote:
It's been over twenty years since I worked in a lab so...

I've had some film developed at a local Costco a couple times in the last
years (don't bother telling me I get what I pay for) I've noticed that the
film they develop shifts blue when it's printed, even when it's printed at
a different lab. I suspect that they are skimping on some replenishment,
for all I know they don't even run controls. Any thoughts on what could
cause a blue shift with c-41 chemistry?

Paul



A consistent blue shift in all frames of a roll of film could only mean
a problem in the processing stage. Since the bleach and fix stages do
not affect color, that would indicate a problem with the developer.
C-41 should only be used once and then discarded. It is possible that
your local Costco was trying to squeeze more than one usage out of the
developer and that it was partially exhausted when used on your film.

Do not despair of the film, however. Individual processing of the
images can solve the printing problem. Machine processing makes
assumptions about color balance, whereas a human being, seeing the blue
shift can add a lot of cyan filtrationto eliminate the effect.


Francis A. Miniter

  #4  
Old December 13th 05, 04:20 PM posted to rec.photo.film+labs
external usenet poster
 
Posts: n/a
Default c-41 color shift


Pdigmking wrote:
It's been over twenty years since I worked in a lab so...

I've had some film developed at a local Costco a couple times in the last
years (don't bother telling me I get what I pay for) I've noticed that the
film they develop shifts blue when it's printed, even when it's printed at
a different lab. I suspect that they are skimping on some replenishment,
for all I know they don't even run controls. Any thoughts on what could
cause a blue shift with c-41 chemistry?

Paul


It's highly unlikely the processing is off. More likely it's a problem
with the film.

  #5  
Old December 13th 05, 09:59 PM posted to rec.photo.film+labs
external usenet poster
 
Posts: n/a
Default c-41 color shift


wrote in message
oups.com...
Pdigmking wrote:
It's been over twenty years since I worked in a lab so...

I've had some film developed at a local Costco a couple times in the

last
years (don't bother telling me I get what I pay for) I've noticed that

the
film they develop shifts blue when it's printed, even when it's printed

at
a different lab. I suspect that they are skimping on some

replenishment,
for all I know they don't even run controls. Any thoughts on what could
cause a blue shift with c-41 chemistry?

Paul



A consistent blue shift in all frames of a roll of film could only mean
a problem in the processing stage. Since the bleach and fix stages do
not affect color, that would indicate a problem with the developer.
C-41 should only be used once and then discarded.


Rubish! Comercial C-41 processing is designed to be replenished. The notion
that a lab could run one film then retank is ridiculous.

It is possible that
your local Costco was trying to squeeze more than one usage out of the
developer and that it was partially exhausted when used on your film.


Why would they skimp on replenishment only to have to retank freqently at
much higher cost?


Do not despair of the film, however. Individual processing of the
images can solve the printing problem. Machine processing makes
assumptions about color balance, whereas a human being, seeing the blue
shift can add a lot of cyan filtrationto eliminate the effect.


How would adding cyan eliminate blue? The original poster should just go
back to the lab and ask them to reprint a little warmer by adding a little
yellow. The chances that this is a processing fault is quite slim and more
likely to be a problem with the film stock or even print viewing conditions.

--
Dooey


  #6  
Old December 14th 05, 05:06 AM posted to rec.photo.film+labs
external usenet poster
 
Posts: n/a
Default c-41 color shift

Just have the negatives printed correctly. There's probably nothing wrong
with your film, just your lab technicians. Color isn't locked into a
negative - it's interpreted every time it's printed.

"Pdigmking" wrote in message
...
It's been over twenty years since I worked in a lab so...

I've had some film developed at a local Costco a couple times in the last
years (don't bother telling me I get what I pay for) I've noticed that
the
film they develop shifts blue when it's printed, even when it's printed at
a different lab. I suspect that they are skimping on some replenishment,
for all I know they don't even run controls. Any thoughts on what could
cause a blue shift with c-41 chemistry?

Paul



  #7  
Old December 14th 05, 05:59 PM posted to rec.photo.film+labs
external usenet poster
 
Posts: n/a
Default c-41 color shift


wrote in message
oups.com...
Pdigmking wrote:
It's been over twenty years since I worked in a lab so...

I've had some film developed at a local Costco a couple times in the last
years (don't bother telling me I get what I pay for) I've noticed that
the
film they develop shifts blue when it's printed, even when it's printed
at
a different lab. I suspect that they are skimping on some replenishment,
for all I know they don't even run controls. Any thoughts on what could
cause a blue shift with c-41 chemistry?

Paul



A consistent blue shift in all frames of a roll of film could only mean
a problem in the processing stage. Since the bleach and fix stages do
not affect color, that would indicate a problem with the developer.
C-41 should only be used once and then discarded. It is possible that
your local Costco was trying to squeeze more than one usage out of the
developer and that it was partially exhausted when used on your film.

Do not despair of the film, however. Individual processing of the
images can solve the printing problem. Machine processing makes
assumptions about color balance, whereas a human being, seeing the blue
shift can add a lot of cyan filtrationto eliminate the effect.


Francis A. Miniter


If the shadow/black areas of the prints have a bluish cast (kind of a
"veil"), that could indicate weak RA-4 developer, or too low developer
temperature.

Have you tried taking the negs somewhere else to have them printed? Perhaps
the local Costco is out of balance on their printer.

(Kodak C-41 developer is available as either a one-shot, or a replenished
version. I prefer the one-shot version for developer, fixer and stabilizer;
the replenished version for bleach, because of the costs and the disposal.
Bleach is a nastier disposal issue than the other chems.)
(The opposite of blue is yellow, cyan is opposite red.)
(Machine printing does make assumptions about color balance, but on a
frame-by-frame basis. If all the frames are of a similar subject matter,
then any 'imbalance' will probably follow the entire roll. If the frames
have different subject matter, then color balances will be different for
each differing frame.)


--
Ken Hart



  #8  
Old December 18th 05, 05:47 AM posted to rec.photo.film+labs
external usenet poster
 
Posts: n/a
Default c-41 color shift


"Ken Hart" wrote

If the shadow/black areas of the prints have a bluish cast (kind of a
"veil"), that could indicate weak RA-4 developer, or too low developer
temperature.


True if the contrast is also very low. This could also be due to a weak
exposure. But if the negs show a good density and the prints are just off
color with a "natural" contrast range, the problem is most likely in the
printing.


 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Forum Jump


All times are GMT +1. The time now is 05:54 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 PhotoBanter.com.
The comments are property of their posters.